From fc8acb61a33974ca022349fac8f682bb355392dc Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 28 Jun 2013 12:02:52 -0400
Subject: [PATCH 01/28] Changed voting dialog to only display one tab per
 answer.

No tests for this, yet.

Conflicts:
	common/lib/xmodule/xmodule/crowdsource_hinter.py
	common/templates/hinter_display.html
---
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 41 +++++++++----------
 .../js/src/crowdsource_hinter/display.coffee  | 13 ++++--
 common/templates/hinter_display.html          | 22 ++++++----
 3 files changed, 43 insertions(+), 33 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 7c7f94a26b..734708ec04 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -188,8 +188,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         Args:
         `data` -- not actually used.  (It is assumed that the answer is correct.)
         Output keys:
-            - 'index_to_hints' maps previous answer indices to hints that the user saw earlier.
-            - 'index_to_answer' maps previous answer indices to the actual answer submitted.
+            - 'answer_to_hints': a nested dictionary.
+              answer_to_hints[answer][hint_pk] returns the text of the hint.
         """
         # The student got it right.
         # Did he submit at least one wrong answer?
@@ -199,27 +199,24 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Make a hint-voting interface for each wrong answer.  The student will only
         # be allowed to make one vote / submission, but he can choose which wrong answer
         # he wants to look at.
-        # index_to_hints[previous answer #] = [(hint text, hint pk), + ]
-        index_to_hints = {}
-        # index_to_answer[previous answer #] = answer text
-        index_to_answer = {}
+        answer_to_hints = {}    #answer_to_hints[answer text][hint pk] -> hint text
 
         # Go through each previous answer, and populate index_to_hints and index_to_answer.
         for i in xrange(len(self.previous_answers)):
             answer, hints_offered = self.previous_answers[i]
-            index_to_hints[i] = []
-            index_to_answer[i] = answer
+            if answer not in answer_to_hints:
+                answer_to_hints[answer] = {}
             if answer in self.hints:
                 # Go through each hint, and add to index_to_hints
                 for hint_id in hints_offered:
-                    if hint_id is not None:
+                    if (hint_id is not None) and (hint_id not in answer_to_hints[answer]):
                         try:
-                            index_to_hints[i].append((self.hints[answer][str(hint_id)][0], hint_id))
+                            answer_to_hints[answer][hint_id] = self.hints[answer][str(hint_id)][0]
                         except KeyError:
                             # Sometimes, the hint that a user saw will have been deleted by the instructor.
                             continue
 
-        return {'index_to_hints': index_to_hints, 'index_to_answer': index_to_answer}
+        return {'answer_to_hints': answer_to_hints}
 
     def tally_vote(self, data):
         """
@@ -229,27 +226,29 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         `data` -- expected to have the following keys:
             'answer': ans_no (index in previous_answers)
             'hint': hint_pk
+            'pk_list': We will return a list of how many votes each hint has so far.
+                       It's up to the browser to specify which hints to return vote counts for.
+                       Every pk listed here will have a hint count returned.
         Returns key 'hint_and_votes', a list of (hint_text, #votes) pairs.
         """
         if self.user_voted:
-            return {}
-        ans_no = int(data['answer'])
-        hint_no = str(data['hint'])
-        answer = self.previous_answers[ans_no][0]
+            return json.dumps({'contents': 'Sorry, but you have already voted!'})
+        ans = data['answer']
+        hint_pk = str(data['hint'])
+        pk_list = json.loads(data['pk_list'])
         # We use temp_dict because we need to do a direct write for the database to update.
         temp_dict = self.hints
-        temp_dict[answer][hint_no][1] += 1
+        temp_dict[ans][hint_pk][1] += 1
         self.hints = temp_dict
         # Don't let the user vote again!
         self.user_voted = True
 
         # Return a list of how many votes each hint got.
         hint_and_votes = []
-        for hint_no in self.previous_answers[ans_no][1]:
-            if hint_no is None:
-                continue
-            hint_and_votes.append(temp_dict[answer][str(hint_no)])
+        for vote_pk in pk_list:
+            hint_and_votes.append(temp_dict[ans][vote_pk])
 
+        hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers.
         self.previous_answers = []
         return {'hint_and_votes': hint_and_votes}
@@ -266,7 +265,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         """
         # Do html escaping.  Perhaps in the future do profanity filtering, etc. as well.
         hint = escape(data['hint'])
-        answer = self.previous_answers[int(data['answer'])][0]
+        answer = data['answer']
         # Only allow a student to vote or submit a hint once.
         if self.user_voted:
             return {'message': 'Sorry, but you have already voted!'}
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 72522f5b03..3df970a618 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -28,6 +28,10 @@ class @Hinter
   $: (selector) ->
     $(selector, @el)
 
+  jq_escape: (string) =>
+    # Escape a string for jquery selector use.
+    return string.replace(/[!"#$%&'()*+,.\/:;<=>?@\[\\\]^`{|}~]/g, '\\$&')
+
   bind: =>
     window.update_schematics()
     @$('input.vote').click @vote
@@ -44,14 +48,17 @@ class @Hinter
 
   vote: (eventObj) =>
     target = @$(eventObj.currentTarget)
-    post_json = {'answer': target.data('answer'), 'hint': target.data('hintno')}
+    parent_div_selector = '#previous-answer-' + @jq_escape(target.attr('data-answer'))
+    all_pks = @$(parent_div_selector).attr('data-all-pks')
+    console.debug(all_pks)
+    post_json = {'answer': target.attr('data-answer'), 'hint': target.data('hintno'), 'pk_list': all_pks}
     $.postWithPrefix "#{@url}/vote", post_json, (response) =>
       @render(response.contents)
 
   submit_hint: (eventObj) =>
     target = @$(eventObj.currentTarget)
-    textarea_id = '#custom-hint-' + target.data('answer')
-    post_json = {'answer': target.data('answer'), 'hint': @$(textarea_id).val()}
+    textarea_id = '#custom-hint-' + @jq_escape(target.attr('data-answer'))
+    post_json = {'answer': target.attr('data-answer'), 'hint': @$(textarea_id).val()}
     $.postWithPrefix "#{@url}/submit_hint",post_json, (response) =>
       @render(response.contents)
 
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 6f5d6f37fb..d349a17fc5 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -25,21 +25,25 @@
 
     <div id="answer-tabs">
         <ul>
-        % for index, answer in index_to_answer.items():
-            <li><a href="#previous-answer-${index}"> ${answer} </a></li>
+        % for answer in answer_to_hints:
+            <li><a href="#previous-answer-${answer}"> ${answer} </a></li> 
         % endfor
         </ul>
 
-        % for index, answer in index_to_answer.items():
-        <div class = "previous-answer" id="previous-answer-${index}">
+        % for answer, pk_dict in answer_to_hints.items():
+        <%
+        import json
+        all_pks = json.dumps(pk_dict.keys())
+        %>
+        <div class = "previous-answer" id="previous-answer-${answer}" data-all-pks='${all_pks}'>
         <div class = "hint-inner-container">
-            % if index in index_to_hints and len(index_to_hints[index]) > 0:
+            % if len(pk_dict) > 0:
                 <p>
                 Which hint would be most effective to show a student who also got ${answer}?
                 </p>
-                % for hint_text, hint_pk in index_to_hints[index]:
+                % for hint_pk, hint_text in pk_dict.items():
                     <p>
-                    <input class="vote" data-answer="${index}" data-hintno="${hint_pk}" type="button" value="Vote"/>
+                    <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
                     ${hint_text}
                     </p>
                 % endfor
@@ -50,12 +54,12 @@
             <p>
             What hint would you give a student who made the same mistake you did?  Please don't give away the answer.
             </p>
-            <textarea cols="50" class="custom-hint" id="custom-hint-${index}">
+            <textarea cols="50" class="custom-hint" id="custom-hint-${answer}">
 What would you say to help someone who got this wrong answer?
 (Don't give away the answer, please.)
             </textarea>
             <br/><br/>
-            <input class="submit-hint" data-answer="${index}" type="button" value="submit">
+            <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
         </div></div>
         % endfor
     </div>

From 69380756d2a45e1147bba360377b9ac6f5f0395c Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 28 Jun 2013 13:49:25 -0400
Subject: [PATCH 02/28] Fixed tests to work with new vote-tabbing method. 
 Fixed some string-int incompatibility errors.

Conflicts:
	common/lib/xmodule/xmodule/crowdsource_hinter.py
	common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
---
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 12 ++++----
 .../xmodule/tests/test_crowdsource_hinter.py  | 28 ++++++++-----------
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 734708ec04..f0f36e7ef8 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -199,7 +199,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Make a hint-voting interface for each wrong answer.  The student will only
         # be allowed to make one vote / submission, but he can choose which wrong answer
         # he wants to look at.
-        answer_to_hints = {}    #answer_to_hints[answer text][hint pk] -> hint text
+        answer_to_hints = {}    # answer_to_hints[answer text][hint pk] -> hint text
 
         # Go through each previous answer, and populate index_to_hints and index_to_answer.
         for i in xrange(len(self.previous_answers)):
@@ -224,7 +224,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
         Args:
         `data` -- expected to have the following keys:
-            'answer': ans_no (index in previous_answers)
+            'answer': text of answer we're voting on
             'hint': hint_pk
             'pk_list': We will return a list of how many votes each hint has so far.
                        It's up to the browser to specify which hints to return vote counts for.
@@ -246,7 +246,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Return a list of how many votes each hint got.
         hint_and_votes = []
         for vote_pk in pk_list:
-            hint_and_votes.append(temp_dict[ans][vote_pk])
+            hint_and_votes.append(temp_dict[ans][str(vote_pk)])
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers.
@@ -259,7 +259,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
         Args:
         `data` -- expected to have the following keys:
-            'answer': answer index in previous_answers
+            'answer': text of answer
             'hint': text of the new hint that the user is adding
         Returns a thank-you message.
         """
@@ -276,9 +276,9 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         else:
             temp_dict = self.hints
         if answer in temp_dict:
-            temp_dict[answer][self.hint_pk] = [hint, 1]     # With one vote (the user himself).
+            temp_dict[answer][str(self.hint_pk)] = [hint, 1]     # With one vote (the user himself).
         else:
-            temp_dict[answer] = {self.hint_pk: [hint, 1]}
+            temp_dict[answer] = {str(self.hint_pk): [hint, 1]}
         self.hint_pk += 1
         if self.moderate == 'True':
             self.mod_queue = temp_dict
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index 19e156a0f3..989b264694 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -294,9 +294,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create(previous_answers=[['26.0', [None, None, None]]])
         json_in = {'problem_name': '42.5'}
         out = mock_module.get_feedback(json_in)
-        print out['index_to_answer']
-        self.assertTrue(out['index_to_hints'][0] == [])
-        self.assertTrue(out['index_to_answer'][0] == '26.0')
+        self.assertTrue(out['answer_to_hints'] == {'26.0': {}})
 
     def test_getfeedback_1wronganswer_withhints(self):
         """
@@ -307,8 +305,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create(previous_answers=[['24.0', [0, 3, None]]])
         json_in = {'problem_name': '42.5'}
         out = mock_module.get_feedback(json_in)
-        print out['index_to_hints']
-        self.assertTrue(len(out['index_to_hints'][0]) == 2)
+        self.assertTrue(len(out['answer_to_hints']['24.0']) == 2)
 
     def test_getfeedback_missingkey(self):
         """
@@ -319,7 +316,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
             previous_answers=[['24.0', [0, 100, None]]])
         json_in = {'problem_name': '42.5'}
         out = mock_module.get_feedback(json_in)
-        self.assertTrue(len(out['index_to_hints'][0]) == 1)
+        self.assertTrue(len(out['answer_to_hints']['24.0']) == 1)
 
     def test_vote_nopermission(self):
         """
@@ -327,7 +324,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         Should not change any vote tallies.
         """
         mock_module = CHModuleFactory.create(user_voted=True)
-        json_in = {'answer': 0, 'hint': 1}
+        json_in = {'answer': '24.0', 'hint': 1, 'pk_list': json.dumps([1, 3])}
         old_hints = copy.deepcopy(mock_module.hints)
         mock_module.tally_vote(json_in)
         self.assertTrue(mock_module.hints == old_hints)
@@ -339,7 +336,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         """
         mock_module = CHModuleFactory.create(
             previous_answers=[['24.0', [0, 3, None]]])
-        json_in = {'answer': 0, 'hint': 3}
+        json_in = {'answer': '24.0', 'hint': 3, 'pk_list': json.dumps([0, 3])}
         dict_out = mock_module.tally_vote(json_in)
         self.assertTrue(mock_module.hints['24.0']['0'][1] == 40)
         self.assertTrue(mock_module.hints['24.0']['3'][1] == 31)
@@ -351,7 +348,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         A user tries to submit a hint, but he has already voted.
         """
         mock_module = CHModuleFactory.create(user_voted=True)
-        json_in = {'answer': 1, 'hint': 'This is a new hint.'}
+        json_in = {'answer': '29.0', 'hint': 'This is a new hint.'}
         print mock_module.user_voted
         mock_module.submit_hint(json_in)
         print mock_module.hints
@@ -363,7 +360,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         exist yet.
         """
         mock_module = CHModuleFactory.create()
-        json_in = {'answer': 1, 'hint': 'This is a new hint.'}
+        json_in = {'answer': '29.0', 'hint': 'This is a new hint.'}
         mock_module.submit_hint(json_in)
         self.assertTrue('29.0' in mock_module.hints)
 
@@ -372,8 +369,8 @@ class CrowdsourceHinterTest(unittest.TestCase):
         A user submits a hint to an answer that has other hints
         already.
         """
-        mock_module = CHModuleFactory.create(previous_answers=[['25.0', [1, None, None]]])
-        json_in = {'answer': 0, 'hint': 'This is a new hint.'}
+        mock_module = CHModuleFactory.create(previous_answers = [['25.0', [1, None, None]]])
+        json_in = {'answer': '25.0', 'hint': 'This is a new hint.'}
         mock_module.submit_hint(json_in)
         # Make a hint request.
         json_in = {'problem name': '25.0'}
@@ -388,7 +385,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         dict.
         """
         mock_module = CHModuleFactory.create(moderate='True')
-        json_in = {'answer': 1, 'hint': 'This is a new hint.'}
+        json_in = {'answer': '29.0', 'hint': 'This is a new hint.'}
         mock_module.submit_hint(json_in)
         self.assertTrue('29.0' not in mock_module.hints)
         self.assertTrue('29.0' in mock_module.mod_queue)
@@ -398,10 +395,9 @@ class CrowdsourceHinterTest(unittest.TestCase):
         Make sure that hints are being html-escaped.
         """
         mock_module = CHModuleFactory.create()
-        json_in = {'answer': 1, 'hint': '<script> alert("Trololo"); </script>'}
+        json_in = {'answer': '29.0', 'hint': '<script> alert("Trololo"); </script>'}
         mock_module.submit_hint(json_in)
-        print mock_module.hints
-        self.assertTrue(mock_module.hints['29.0'][0][0] == u'&lt;script&gt; alert(&quot;Trololo&quot;); &lt;/script&gt;')
+        self.assertTrue(mock_module.hints['29.0']['0'][0] == u'&lt;script&gt; alert(&quot;Trololo&quot;); &lt;/script&gt;')
 
     def test_template_gethint(self):
         """

From c34a81a845b72b7c7e2f714ac9300682c4a81534 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Wed, 10 Jul 2013 13:11:50 -0400
Subject: [PATCH 03/28] Refactored formula response grader to expose
 formula-evaluating to outside world.

In preparation for adding hints to formula response.
---
 common/lib/capa/capa/responsetypes.py | 88 ++++++++++++++-------------
 1 file changed, 47 insertions(+), 41 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 731230ecc1..c3d680ee20 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -1778,46 +1778,24 @@ class FormulaResponse(LoncapaResponse):
             self.correct_answer, given, self.samples)
         return CorrectMap(self.answer_id, correctness)
 
-    def check_formula(self, expected, given, samples):
-        variables = samples.split('@')[0].split(',')
-        numsamples = int(samples.split('@')[1].split('#')[1])
-        sranges = zip(*map(lambda x: map(float, x.split(",")),
-                           samples.split('@')[1].split('#')[0].split(':')))
-
-        ranges = dict(zip(variables, sranges))
-        for _ in range(numsamples):
-            instructor_variables = self.strip_dict(dict(self.context))
-            student_variables = {}
-            # ranges give numerical ranges for testing
-            for var in ranges:
-                # TODO: allow specified ranges (i.e. integers and complex numbers) for random variables
-                value = random.uniform(*ranges[var])
-                instructor_variables[str(var)] = value
-                student_variables[str(var)] = value
-            # log.debug('formula: instructor_vars=%s, expected=%s' %
-            # (instructor_variables,expected))
-
-            # Call `evaluator` on the instructor's answer and get a number
-            instructor_result = evaluator(
-                instructor_variables, {},
-                expected, case_sensitive=self.case_sensitive
-            )
+    def hash_answers(self, answer, var_dict_list):
+        """
+        Takes in an answer and a list of dictionaries mapping variables to values.
+        Each dictionary represents a test case for the answer.
+        Returns a tuple of formula evaluation results.
+        """
+        out = []
+        for var_dict in var_dict_list:
             try:
-                # log.debug('formula: student_vars=%s, given=%s' %
-                # (student_variables,given))
-
-                # Call `evaluator` on the student's answer; look for exceptions
-                student_result = evaluator(
-                    student_variables,
-                    {},
-                    given,
-                    case_sensitive=self.case_sensitive
-                )
+                out.append(evaluator(
+                    var_dict,
+                    dict(),
+                    answer,
+                    cs=self.case_sensitive,
+                ))
             except UndefinedVariable as uv:
                 log.debug(
-                    'formularesponse: undefined variable in given=%s',
-                    given
-                )
+                    'formularesponse: undefined variable in formula=%s' % answer)
                 raise StudentInputError(
                     "Invalid input: " + uv.message + " not permitted in answer"
                 )
@@ -1840,15 +1818,43 @@ class FormulaResponse(LoncapaResponse):
                 # If non-factorial related ValueError thrown, handle it the same as any other Exception
                 log.debug('formularesponse: error {0} in formula'.format(ve))
                 raise StudentInputError("Invalid input: Could not parse '%s' as a formula" %
-                                        cgi.escape(given))
+                                        cgi.escape(answer))
             except Exception as err:
                 # traceback.print_exc()
                 log.debug('formularesponse: error %s in formula', err)
                 raise StudentInputError("Invalid input: Could not parse '%s' as a formula" %
-                                        cgi.escape(given))
+                                        cgi.escape(answer))
+        return tuple(out)
 
-            # No errors in student's response--actually test for correctness
-            if not compare_with_tolerance(student_result, instructor_result, self.tolerance):
+    def randomize_variables(self, samples):
+        """
+        Returns a list of dictionaries mapping variables to random values in range,
+        as expected by hash_answers.
+        """
+        variables = samples.split('@')[0].split(',')
+        numsamples = int(samples.split('@')[1].split('#')[1])
+        sranges = zip(*map(lambda x: map(float, x.split(",")),
+                           samples.split('@')[1].split('#')[0].split(':')))
+        ranges = dict(zip(variables, sranges))
+
+        out = []
+        for i in range(numsamples):
+            var_dict = {}
+            # ranges give numerical ranges for testing
+            for var in ranges:
+                # TODO: allow specified ranges (i.e. integers and complex numbers) for random variables
+                value = random.uniform(*ranges[var])
+                var_dict[str(var)] = value
+            out.append(var_dict)
+        return out
+
+    def check_formula(self, expected, given, samples):
+        var_dict_list = self.randomize_variables(samples)
+        student_result = self.hash_answers(given, var_dict_list)
+        instructor_result = self.hash_answers(expected, var_dict_list)
+
+        for i in xrange(len(instructor_result)):
+            if not compare_with_tolerance(student_result[i], instructor_result[i], self.tolerance):
                 return "incorrect"
         return "correct"
 

From b88c6b8d68fc99207ab640304ec816a022e0bbe5 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 11 Jul 2013 11:12:12 -0400
Subject: [PATCH 04/28] Hinter now works with formula responses.  Tests broken.

---
 common/lib/capa/capa/responsetypes.py         |   2 +-
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 102 ++++++++++++++----
 2 files changed, 82 insertions(+), 22 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index c3d680ee20..47289aad51 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -1824,7 +1824,7 @@ class FormulaResponse(LoncapaResponse):
                 log.debug('formularesponse: error %s in formula', err)
                 raise StudentInputError("Invalid input: Could not parse '%s' as a formula" %
                                         cgi.escape(answer))
-        return tuple(out)
+        return out
 
     def randomize_variables(self, samples):
         """
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index f0f36e7ef8..6c868cb621 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -16,6 +16,8 @@ from xmodule.x_module import XModule
 from xmodule.xml_module import XmlDescriptor
 from xblock.core import Scope, String, Integer, Boolean, Dict, List
 
+from capa.responsetypes import FormulaResponse, StudentInputError
+
 from django.utils.html import escape
 
 log = logging.getLogger(__name__)
@@ -37,6 +39,14 @@ class CrowdsourceHinterFields(object):
     mod_queue = Dict(help='A dictionary containing hints still awaiting approval', scope=Scope.content,
                      default={})
     hint_pk = Integer(help='Used to index hints.', scope=Scope.content, default=0)
+    # signature_to_ans maps an answer signature to an answer string that shows that answer in a
+    # human-readable form.
+    signature_to_ans = Dict(help='Maps a signature to a representative formula.', scope=Scope.content,
+                            default={})
+    # A list of dictionaries, each of which represents an n-dimenstional point that we plug into
+    # formulas.  Each dictionary maps variables to values, eg {'x': 5.1}.
+    formula_test_values = List(help='The values that we plug into formula responses', scope=Scope.content,
+                               default=[])
     # A list of previous answers this student made to this problem.
     # Of the form [answer, [hint_pk_1, hint_pk_2, hint_pk_3]] for each problem.  hint_pk's are
     # None if the hint was not given.
@@ -68,6 +78,15 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
+        # We need to know whether we are working with a FormulaResponse problem.
+        self.is_formula = (type(self.get_display_items()[0].lcp.responders.values()[0]) == FormulaResponse)
+        if self.is_formula:
+            self.answer_to_str = self.formula_answer_to_str
+            self.answer_signature = self.formula_answer_signature
+        else:
+            self.answer_to_str = self.numerical_answer_to_str
+            # Right now, numerical problems don't need special answer signature treatment.
+            self.answer_signature = lambda x: x
 
     def get_html(self):
         """
@@ -98,15 +117,45 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
         return out
 
-    def capa_answer_to_str(self, answer):
+    def numerical_answer_to_str(self, answer):
         """
-        Converts capa answer format to a string representation
+        Converts capa numerical answer format to a string representation
         of the answer.
         -Lon-capa dependent.
         -Assumes that the problem only has one part.
         """
         return str(float(answer.values()[0]))
 
+    def formula_answer_to_str(self, answer):
+        """
+        Converts capa formula answer into a string.
+        -Lon-capa dependent.
+        -Assumes that the problem only has one part.
+        """
+        return str(answer.values()[0])
+
+    def formula_answer_signature(self, answer):
+        """
+        Converts a capa answer string (output of formula_answer_to_str)
+        to a string unique to each formula equality class.
+        So, x^2 and x*x would have the same signature, which would differ
+        from the signature of 2*x^2.
+        """
+        responder = self.get_display_items()[0].lcp.responders.values()[0]
+        if self.formula_test_values == []:
+            # Make a set of test values, and save them.
+            self.formula_test_values = responder.randomize_variables(responder.samples)
+        try:
+            # TODO, maybe: add some rounding to signature generation, so that floating point
+            # errors don't make a difference.
+            out = str(responder.hash_answers(answer, self.formula_test_values))
+        except StudentInputError:
+            # I'm not sure what's the best thing to do here.
+            # I'll return the empty string, for now.
+            # That way, all invalid hints are clustered together.
+            return ''
+        return out
+
     def handle_ajax(self, dispatch, data):
         """
         This is the landing method for AJAX calls.
@@ -134,44 +183,46 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
         Called by hinter javascript after a problem is graded as incorrect.
         Args:
-        `data` -- must be interpretable by capa_answer_to_str.
+        `data` -- must be interpretable by answer_to_str.
         Output keys:
             - 'best_hint' is the hint text with the most votes.
             - 'rand_hint_1' and 'rand_hint_2' are two random hints to the answer in `data`.
             - 'answer' is the parsed answer that was submitted.
         """
         try:
-            answer = self.capa_answer_to_str(data)
+            answer = self.answer_to_str(data)
         except ValueError:
             # Sometimes, we get an answer that's just not parsable.  Do nothing.
             log.exception('Answer not parsable: ' + str(data))
             return
+        # Make a signature of the answer, for formula responses.
+        signature = self.answer_signature(answer)
         # Look for a hint to give.
         # Make a local copy of self.hints - this means we only need to do one json unpacking.
         # (This is because xblocks storage makes the following command a deep copy.)
         local_hints = self.hints
-        if (answer not in local_hints) or (len(local_hints[answer]) == 0):
+        if (signature not in local_hints) or (len(local_hints[signature]) == 0):
             # No hints to give.  Return.
             self.previous_answers += [[answer, [None, None, None]]]
             return
         # Get the top hint, plus two random hints.
-        n_hints = len(local_hints[answer])
-        best_hint_index = max(local_hints[answer], key=lambda key: local_hints[answer][key][1])
-        best_hint = local_hints[answer][best_hint_index][0]
-        if len(local_hints[answer]) == 1:
+        n_hints = len(local_hints[signature])
+        best_hint_index = max(local_hints[signature], key=lambda key: local_hints[signature][key][1])
+        best_hint = local_hints[signature][best_hint_index][0]
+        if len(local_hints[signature]) == 1:
             rand_hint_1 = ''
             rand_hint_2 = ''
             self.previous_answers += [[answer, [best_hint_index, None, None]]]
         elif n_hints == 2:
-            best_hint = local_hints[answer].values()[0][0]
-            best_hint_index = local_hints[answer].keys()[0]
-            rand_hint_1 = local_hints[answer].values()[1][0]
-            hint_index_1 = local_hints[answer].keys()[1]
+            best_hint = local_hints[signature].values()[0][0]
+            best_hint_index = local_hints[signature].keys()[0]
+            rand_hint_1 = local_hints[signature].values()[1][0]
+            hint_index_1 = local_hints[signature].keys()[1]
             rand_hint_2 = ''
             self.previous_answers += [[answer, [best_hint_index, hint_index_1, None]]]
         else:
             (hint_index_1, rand_hint_1), (hint_index_2, rand_hint_2) =\
-                random.sample(local_hints[answer].items(), 2)
+                random.sample(local_hints[signature].items(), 2)
             rand_hint_1 = rand_hint_1[0]
             rand_hint_2 = rand_hint_2[0]
             self.previous_answers += [[answer, [best_hint_index, hint_index_1, hint_index_2]]]
@@ -206,12 +257,13 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             answer, hints_offered = self.previous_answers[i]
             if answer not in answer_to_hints:
                 answer_to_hints[answer] = {}
-            if answer in self.hints:
+            signature = self.answer_signature(answer)
+            if signature in self.hints:
                 # Go through each hint, and add to index_to_hints
                 for hint_id in hints_offered:
-                    if (hint_id is not None) and (hint_id not in answer_to_hints[answer]):
+                    if (hint_id is not None) and (hint_id not in answer_to_hints[signature]):
                         try:
-                            answer_to_hints[answer][hint_id] = self.hints[answer][str(hint_id)][0]
+                            answer_to_hints[answer][hint_id] = self.hints[signature][str(hint_id)][0]
                         except KeyError:
                             # Sometimes, the hint that a user saw will have been deleted by the instructor.
                             continue
@@ -234,11 +286,12 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         if self.user_voted:
             return json.dumps({'contents': 'Sorry, but you have already voted!'})
         ans = data['answer']
+        signature = self.answer_signature(ans)
         hint_pk = str(data['hint'])
         pk_list = json.loads(data['pk_list'])
         # We use temp_dict because we need to do a direct write for the database to update.
         temp_dict = self.hints
-        temp_dict[ans][hint_pk][1] += 1
+        temp_dict[signature][hint_pk][1] += 1
         self.hints = temp_dict
         # Don't let the user vote again!
         self.user_voted = True
@@ -246,7 +299,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Return a list of how many votes each hint got.
         hint_and_votes = []
         for vote_pk in pk_list:
-            hint_and_votes.append(temp_dict[ans][str(vote_pk)])
+            hint_and_votes.append(temp_dict[signature][str(vote_pk)])
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers.
@@ -266,6 +319,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Do html escaping.  Perhaps in the future do profanity filtering, etc. as well.
         hint = escape(data['hint'])
         answer = data['answer']
+        signature = self.answer_signature(answer)
         # Only allow a student to vote or submit a hint once.
         if self.user_voted:
             return {'message': 'Sorry, but you have already voted!'}
@@ -276,9 +330,15 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         else:
             temp_dict = self.hints
         if answer in temp_dict:
-            temp_dict[answer][str(self.hint_pk)] = [hint, 1]     # With one vote (the user himself).
+            temp_dict[signature][str(self.hint_pk)] = [hint, 1]     # With one vote (the user himself).
         else:
-            temp_dict[answer] = {str(self.hint_pk): [hint, 1]}
+            temp_dict[signature] = {str(self.hint_pk): [hint, 1]}
+        # Add the signature to signature_to_ans, if it's not there yet.
+        # This allows instructors to see a human-readable answer that corresponds to each signature.
+        if answer not in self.signature_to_ans:
+            local_sta = self.signature_to_ans
+            local_sta[signature] = answer
+            self.signature_to_ans = local_sta
         self.hint_pk += 1
         if self.moderate == 'True':
             self.mod_queue = temp_dict

From 199b6325137e7cef6f36e1be3c9113680b5d0eb1 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 11 Jul 2013 17:15:01 -0400
Subject: [PATCH 05/28] Crowdsourced hinter now supports formula responses. 
 Tests still broken.

---
 .../lib/xmodule/xmodule/crowdsource_hinter.py |  33 ++++--
 .../js/src/crowdsource_hinter/display.coffee  |   9 +-
 common/templates/hinter_display.html          |  15 ++-
 lms/djangoapps/instructor/hint_manager.py     | 103 ++++++++++++------
 .../hint_manager.html                         |   2 +-
 .../hint_manager_inner.html                   |   6 +-
 6 files changed, 116 insertions(+), 52 deletions(-)
 rename lms/templates/{courseware => instructor}/hint_manager.html (98%)
 rename lms/templates/{courseware => instructor}/hint_manager_inner.html (90%)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 6c868cb621..bac6982085 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -13,7 +13,7 @@ from pkg_resources import resource_string
 from lxml import etree
 
 from xmodule.x_module import XModule
-from xmodule.xml_module import XmlDescriptor
+from xmodule.raw_module import RawDescriptor
 from xblock.core import Scope, String, Integer, Boolean, Dict, List
 
 from capa.responsetypes import FormulaResponse, StudentInputError
@@ -150,10 +150,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             # errors don't make a difference.
             out = str(responder.hash_answers(answer, self.formula_test_values))
         except StudentInputError:
-            # I'm not sure what's the best thing to do here.
-            # I'll return the empty string, for now.
-            # That way, all invalid hints are clustered together.
-            return ''
+            # I'm not sure what's the best thing to do here.  I'm returning
+            # None, for now, so that the calling function has a chance to catch
+            # the error without having to import StudentInputError.
+            return None
         return out
 
     def handle_ajax(self, dispatch, data):
@@ -197,6 +197,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             return
         # Make a signature of the answer, for formula responses.
         signature = self.answer_signature(answer)
+        if signature == None:
+            # Sometimes, signature conversion may fail.
+            log.exception('Signature conversion failed: ' + str(answer))
+            return
         # Look for a hint to give.
         # Make a local copy of self.hints - this means we only need to do one json unpacking.
         # (This is because xblocks storage makes the following command a deep copy.)
@@ -261,7 +265,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             if signature in self.hints:
                 # Go through each hint, and add to index_to_hints
                 for hint_id in hints_offered:
-                    if (hint_id is not None) and (hint_id not in answer_to_hints[signature]):
+                    if (hint_id is not None) and (hint_id not in answer_to_hints[answer]):
                         try:
                             answer_to_hints[answer][hint_id] = self.hints[signature][str(hint_id)][0]
                         except KeyError:
@@ -335,10 +339,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             temp_dict[signature] = {str(self.hint_pk): [hint, 1]}
         # Add the signature to signature_to_ans, if it's not there yet.
         # This allows instructors to see a human-readable answer that corresponds to each signature.
-        if answer not in self.signature_to_ans:
-            local_sta = self.signature_to_ans
-            local_sta[signature] = answer
-            self.signature_to_ans = local_sta
+        self.add_signature(signature, answer)
         self.hint_pk += 1
         if self.moderate == 'True':
             self.mod_queue = temp_dict
@@ -349,8 +350,18 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         self.previous_answers = []
         return {'message': 'Thank you for your hint!'}
 
+    def add_signature(self, signature, answer):
+        """
+        Add a signature to self.signature_to_ans.  If the signature already
+        exists, do nothing.
+        """
+        if signature not in self.signature_to_ans:
+            local_sta = self.signature_to_ans
+            local_sta[signature] = answer
+            self.signature_to_ans = local_sta
 
-class CrowdsourceHinterDescriptor(CrowdsourceHinterFields, XmlDescriptor):
+
+class CrowdsourceHinterDescriptor(CrowdsourceHinterFields, RawDescriptor):
     module_class = CrowdsourceHinterModule
     stores_state = True
 
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 3df970a618..2e4d0e2c3b 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -48,8 +48,8 @@ class @Hinter
 
   vote: (eventObj) =>
     target = @$(eventObj.currentTarget)
-    parent_div_selector = '#previous-answer-' + @jq_escape(target.attr('data-answer'))
-    all_pks = @$(parent_div_selector).attr('data-all-pks')
+    parent_div = $('.previous-answer[data-answer="'+target.attr('data-answer')+'"]')
+    all_pks = parent_div.attr('data-all-pks')
     console.debug(all_pks)
     post_json = {'answer': target.attr('data-answer'), 'hint': target.data('hintno'), 'pk_list': all_pks}
     $.postWithPrefix "#{@url}/vote", post_json, (response) =>
@@ -57,8 +57,9 @@ class @Hinter
 
   submit_hint: (eventObj) =>
     target = @$(eventObj.currentTarget)
-    textarea_id = '#custom-hint-' + @jq_escape(target.attr('data-answer'))
-    post_json = {'answer': target.attr('data-answer'), 'hint': @$(textarea_id).val()}
+    textarea = $('.custom-hint[data-answer="'+target.attr('data-answer')+'"]')
+    console.debug(textarea)
+    post_json = {'answer': target.attr('data-answer'), 'hint': @$(textarea).val()}
     $.postWithPrefix "#{@url}/submit_hint",post_json, (response) =>
       @render(response.contents)
 
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index d349a17fc5..4f40113265 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -23,10 +23,19 @@
     Help your classmates by writing hints for this problem. Start by picking one of your previous incorrect answers from below:
     </p>
 
+    <%
+    def unspace(string):
+        """
+        HTML id's can't have spaces in them.  This little function
+        removes spaces.
+        """
+        return ''.join(string.split())
+    %>
+
     <div id="answer-tabs">
         <ul>
         % for answer in answer_to_hints:
-            <li><a href="#previous-answer-${answer}"> ${answer} </a></li> 
+            <li><a href="#previous-answer-${unspace(answer)}"> ${answer} </a></li>
         % endfor
         </ul>
 
@@ -35,7 +44,7 @@
         import json
         all_pks = json.dumps(pk_dict.keys())
         %>
-        <div class = "previous-answer" id="previous-answer-${answer}" data-all-pks='${all_pks}'>
+        <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}" data-all-pks='${all_pks}'>
         <div class = "hint-inner-container">
             % if len(pk_dict) > 0:
                 <p>
@@ -54,7 +63,7 @@
             <p>
             What hint would you give a student who made the same mistake you did?  Please don't give away the answer.
             </p>
-            <textarea cols="50" class="custom-hint" id="custom-hint-${answer}">
+            <textarea cols="50" class="custom-hint" data-answer="${answer}">
 What would you say to help someone who got this wrong answer?
 (Don't give away the answer, please.)
             </textarea>
diff --git a/lms/djangoapps/instructor/hint_manager.py b/lms/djangoapps/instructor/hint_manager.py
index 899e386f70..b20cdc81e6 100644
--- a/lms/djangoapps/instructor/hint_manager.py
+++ b/lms/djangoapps/instructor/hint_manager.py
@@ -10,11 +10,14 @@ import re
 
 from django.http import HttpResponse, Http404
 from django_future.csrf import ensure_csrf_cookie
+from django.core.exceptions import ObjectDoesNotExist
 
 from mitxmako.shortcuts import render_to_response, render_to_string
 
 from courseware.courses import get_course_with_access
 from courseware.models import XModuleContentField
+from courseware.module_render import get_module
+from courseware.model_data import ModelDataCache
 from xmodule.modulestore import Location
 from xmodule.modulestore.django import modulestore
 
@@ -28,24 +31,29 @@ def hint_manager(request, course_id):
         return HttpResponse(out)
     if request.method == 'GET':
         out = get_hints(request, course_id, 'mod_queue')
-        return render_to_response('courseware/hint_manager.html', out)
+        out.update({'error': ''})
+        return render_to_response('instructor/hint_manager.html', out)
     field = request.POST['field']
     if not (field == 'mod_queue' or field == 'hints'):
         # Invalid field.  (Don't let users continue - they may overwrite other db's)
         out = 'Error in hint manager - an invalid field was accessed.'
         return HttpResponse(out)
 
-    if request.POST['op'] == 'delete hints':
-        delete_hints(request, course_id, field)
-    if request.POST['op'] == 'switch fields':
-        pass
-    if request.POST['op'] == 'change votes':
-        change_votes(request, course_id, field)
-    if request.POST['op'] == 'add hint':
-        add_hint(request, course_id, field)
-    if request.POST['op'] == 'approve':
-        approve(request, course_id, field)
-    rendered_html = render_to_string('courseware/hint_manager_inner.html', get_hints(request, course_id, field))
+    switch_dict = {
+        'delete hints': delete_hints,
+        'switch fields': lambda *args: None,    # Takes any number of arguments, returns None.
+        'change votes': change_votes,
+        'add hint': add_hint,
+        'approve': approve,
+    }
+
+    # Do the operation requested, and collect any error messages.
+    error_text = switch_dict[request.POST['op']](request, course_id, field)
+    if error_text is None:
+        error_text = ''
+    render_dict = get_hints(request, course_id, field)
+    render_dict.update({'error': error_text})
+    rendered_html = render_to_string('instructor/hint_manager_inner.html', render_dict)
     return HttpResponse(json.dumps({'success': True, 'contents': rendered_html}))
 
 
@@ -106,8 +114,27 @@ def get_hints(request, course_id, field):
                 # Put all non-numerical answers first.
                 return float('-inf')
 
-        # Answer list contains [answer, dict_of_hints] pairs.
-        answer_list = sorted(json.loads(hints_by_problem.value).items(), key=answer_sorter)
+        # Find the signature to answer converter for this problem.  Sometimes,
+        # it doesn't exist; just assume that the signatures are the answers.
+        try:
+            signature_to_ans = XModuleContentField.objects.get(
+                field_name='signature_to_ans',
+                definition_id__regex=chopped_id
+            )
+            signature_to_ans = json.loads(signature_to_ans.value)
+        except ObjectDoesNotExist:
+            signature_to_ans = {}
+
+        signatures_dict = json.loads(hints_by_problem.value)
+        unsorted = []
+        for signature, dict_of_hints in signatures_dict.items():
+            if signature in signature_to_ans:
+                ans_txt = signature_to_ans[signature]
+            else:   
+                ans_txt = signature
+            unsorted.append([signature, ans_txt, dict_of_hints])
+        # Answer list contains [signature, answer, dict_of_hints] sub-lists.
+        answer_list = sorted(unsorted, key=answer_sorter)
         big_out_dict[hints_by_problem.definition_id] = answer_list
 
     render_dict = {'field': field,
@@ -138,7 +165,7 @@ def delete_hints(request, course_id, field):
     Deletes the hints specified.
 
     `request.POST` contains some fields keyed by integers.  Each such field contains a
-    [problem_defn_id, answer, pk] tuple.  These tuples specify the hints to be deleted.
+    [problem_defn_id, signature, pk] tuple.  These tuples specify the hints to be deleted.
 
     Example `request.POST`:
     {'op': 'delete_hints',
@@ -150,12 +177,12 @@ def delete_hints(request, course_id, field):
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, answer, pk = request.POST.getlist(key)
+        problem_id, signature, pk = request.POST.getlist(key)
         # Can be optimized - sort the delete list by problem_id, and load each problem
         # from the database only once.
         this_problem = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(this_problem.value)
-        del problem_dict[answer][pk]
+        del problem_dict[signature][pk]
         this_problem.value = json.dumps(problem_dict)
         this_problem.save()
 
@@ -164,18 +191,18 @@ def change_votes(request, course_id, field):
     """
     Updates the number of votes.
 
-    The numbered fields of `request.POST` contain [problem_id, answer, pk, new_votes] tuples.
+    The numbered fields of `request.POST` contain [problem_id, signature, pk, new_votes] tuples.
     - Very similar to `delete_hints`.  Is there a way to merge them?  Nah, too complicated.
     """
 
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, answer, pk, new_votes = request.POST.getlist(key)
+        problem_id, signature, pk, new_votes = request.POST.getlist(key)
         this_problem = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(this_problem.value)
-        # problem_dict[answer][pk] points to a [hint_text, #votes] pair.
-        problem_dict[answer][pk][1] = int(new_votes)
+        # problem_dict[signature][pk] points to a [hint_text, #votes] pair.
+        problem_dict[signature][pk][1] = int(new_votes)
         this_problem.value = json.dumps(problem_dict)
         this_problem.save()
 
@@ -187,6 +214,7 @@ def add_hint(request, course_id, field):
     field
     problem - The problem id
     answer - The answer to which a hint will be added
+           - Needs to be converted into signature first.
     hint - The text of the hint
     """
 
@@ -200,10 +228,23 @@ def add_hint(request, course_id, field):
     hint_pk_entry.value = this_pk + 1
     hint_pk_entry.save()
 
+    # Make signature.  This is really annoying, but I don't see
+    # any alternative :(
+    loc = Location(problem_id)
+    descriptors = modulestore().get_items(loc)
+    m_d_c = ModelDataCache(descriptors, course_id, request.user)
+    hinter_module = get_module(request.user, request, loc, m_d_c, course_id)
+    signature = hinter_module.answer_signature(answer)
+    if signature is None:
+        # Signature generation failed.
+        # We should probably return an error message, too... working on that.
+        return 'Error - your answer could not be parsed as a formula expression.'
+    hinter_module.add_signature(signature, answer)
+
     problem_dict = json.loads(this_problem.value)
-    if answer not in problem_dict:
-        problem_dict[answer] = {}
-    problem_dict[answer][this_pk] = [hint_text, 1]
+    if signature not in problem_dict:
+        problem_dict[signature] = {}
+    problem_dict[signature][this_pk] = [hint_text, 1]
     this_problem.value = json.dumps(problem_dict)
     this_problem.save()
 
@@ -213,26 +254,26 @@ def approve(request, course_id, field):
     Approve a list of hints, moving them from the mod_queue to the real
     hint list.  POST:
     op, field
-    (some number) -> [problem, answer, pk]
+    (some number) -> [problem, signature, pk]
     """
 
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, answer, pk = request.POST.getlist(key)
+        problem_id, signature, pk = request.POST.getlist(key)
         # Can be optimized - sort the delete list by problem_id, and load each problem
         # from the database only once.
         problem_in_mod = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(problem_in_mod.value)
-        hint_to_move = problem_dict[answer][pk]
-        del problem_dict[answer][pk]
+        hint_to_move = problem_dict[signature][pk]
+        del problem_dict[signature][pk]
         problem_in_mod.value = json.dumps(problem_dict)
         problem_in_mod.save()
 
         problem_in_hints = XModuleContentField.objects.get(field_name='hints', definition_id=problem_id)
         problem_dict = json.loads(problem_in_hints.value)
-        if answer not in problem_dict:
-            problem_dict[answer] = {}
-        problem_dict[answer][pk] = hint_to_move
+        if signature not in problem_dict:
+            problem_dict[signature] = {}
+        problem_dict[signature][pk] = hint_to_move
         problem_in_hints.value = json.dumps(problem_dict)
         problem_in_hints.save()
diff --git a/lms/templates/courseware/hint_manager.html b/lms/templates/instructor/hint_manager.html
similarity index 98%
rename from lms/templates/courseware/hint_manager.html
rename to lms/templates/instructor/hint_manager.html
index ebd7091a09..4a6e219560 100644
--- a/lms/templates/courseware/hint_manager.html
+++ b/lms/templates/instructor/hint_manager.html
@@ -1,6 +1,6 @@
 <%inherit file="/main.html" />
 <%namespace name='static' file='/static_content.html'/>
-<%namespace name="content" file="/courseware/hint_manager_inner.html"/>
+<%namespace name="content" file="/instructor/hint_manager_inner.html"/>
 
 
 <%block name="headextra">
diff --git a/lms/templates/courseware/hint_manager_inner.html b/lms/templates/instructor/hint_manager_inner.html
similarity index 90%
rename from lms/templates/courseware/hint_manager_inner.html
rename to lms/templates/instructor/hint_manager_inner.html
index c69539522f..3acf8102ac 100644
--- a/lms/templates/courseware/hint_manager_inner.html
+++ b/lms/templates/instructor/hint_manager_inner.html
@@ -4,15 +4,16 @@
 <h1> ${field_label} </h1>
 Switch to <a id="switch-fields" other-field="${other_field}">${other_field_label}</a>
 
+<p style="color:red"> ${error} </p>
 
 % for definition_id in all_hints:
     <h2> Problem: ${id_to_name[definition_id]} </h2>
-    % for answer, hint_dict in all_hints[definition_id]:
+    % for signature, answer, hint_dict in all_hints[definition_id]:
         % if len(hint_dict) > 0:
             <h4> Answer: ${answer} </h4><div style="background-color:#EEEEEE">
         % endif
         % for pk, hint in hint_dict.items():
-            <p data-problem="${definition_id}" data-pk="${pk}" data-answer="${answer}">
+            <p data-problem="${definition_id}" data-pk="${pk}" data-answer="${signature}">
                 <input class="hint-select" type="checkbox"/> ${hint[0]}
                 <br /> 
                 Votes: <input type="text" class="votes" value="${str(hint[1])}" style="font-size:12px; height:20px; width:50px"></input>
@@ -36,6 +37,7 @@ Switch to <a id="switch-fields" other-field="${other_field}">${other_field_label
     <br />
 % endfor
 
+<p style="color:red"> ${error} </p>
 <button id="hint-delete"> Delete selected </button> <button id="update-votes"> Update votes </button>
 
 % if field == 'mod_queue':

From a730f9189bc32558995937ef72aae687a3f9c8be Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Mon, 15 Jul 2013 11:25:59 -0400
Subject: [PATCH 06/28] Fixed numerous 500 errors that result from
 mal-formatted post requests.

Fixed tests to work with symbolic answer changes.
---
 .../lib/xmodule/xmodule/crowdsource_hinter.py |  24 +++-
 .../xmodule/tests/test_crowdsource_hinter.py  | 135 +++++++++++++++++-
 common/templates/hinter_display.html          |   4 +
 3 files changed, 158 insertions(+), 5 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index bac6982085..5c5c869088 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -173,6 +173,9 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
 
         if out is None:
             out = {'op': 'empty'}
+        elif 'error' in out:
+            # Error in processing.
+            out.update({'op': 'error'})
         else:
             out.update({'op': dispatch})
         return json.dumps({'contents': self.system.render_template('hinter_display.html', out)})
@@ -288,14 +291,23 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         Returns key 'hint_and_votes', a list of (hint_text, #votes) pairs.
         """
         if self.user_voted:
-            return json.dumps({'contents': 'Sorry, but you have already voted!'})
+            return {'error': 'Sorry, but you have already voted!'}
         ans = data['answer']
         signature = self.answer_signature(ans)
+        if signature is None:
+            # Uh oh.  Invalid answer.
+            log.exception('Failure in hinter tally_vote: Unable to parse answer: ' + ans)
+            return {'error': 'Failure in voting!'}
         hint_pk = str(data['hint'])
         pk_list = json.loads(data['pk_list'])
         # We use temp_dict because we need to do a direct write for the database to update.
         temp_dict = self.hints
-        temp_dict[signature][hint_pk][1] += 1
+        try:
+            temp_dict[signature][hint_pk][1] += 1
+        except KeyError:
+            log.exception('Failure in hinter tally_vote: User voted for non-existant hint: Answer=' +
+                          ans + ' pk=' + hint_pk)
+            return {'error': 'Failure in voting!'}
         self.hints = temp_dict
         # Don't let the user vote again!
         self.user_voted = True
@@ -303,7 +315,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Return a list of how many votes each hint got.
         hint_and_votes = []
         for vote_pk in pk_list:
-            hint_and_votes.append(temp_dict[signature][str(vote_pk)])
+            try:
+                hint_and_votes.append(temp_dict[signature][str(vote_pk)])
+            except KeyError:
+                log.exception('In hinter tally_vote: pk_list contains non-existant pk: ' + str(vote_pk))
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers.
@@ -324,6 +339,9 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         hint = escape(data['hint'])
         answer = data['answer']
         signature = self.answer_signature(answer)
+        if signature is None:
+            log.exception('Failure in hinter submit_hint: Unable to parse answer: ' + answer)
+            return {'error': 'Could not submit answer'}
         # Only allow a student to vote or submit a hint once.
         if self.user_voted:
             return {'message': 'Sorry, but you have already voted!'}
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index 989b264694..b8a205e90e 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -2,13 +2,15 @@
 Tests the crowdsourced hinter xmodule.
 """
 
-from mock import Mock
+from mock import Mock, MagicMock
 import unittest
 import copy
 
 from xmodule.crowdsource_hinter import CrowdsourceHinterModule
 from xmodule.vertical_module import VerticalModule, VerticalDescriptor
 
+from capa.responsetypes import StudentInputError
+
 from . import get_test_system
 
 import json
@@ -94,12 +96,54 @@ class CHModuleFactory(object):
         if moderate is not None:
             model_data['moderate'] = moderate
 
-        descriptor = Mock(weight="1")
+        descriptor = Mock(weight='1')
+        # Make the descriptor have a capa problem child.
+        capa_descriptor = MagicMock()
+        capa_descriptor.name = 'capa'
+        descriptor.get_children = lambda: [capa_descriptor]
+
+        # Make a fake capa module.
+        capa_module = MagicMock()
+        capa_module.responders = {'responder0': MagicMock()}
+        capa_module.displayable_items = lambda: [capa_module]
+
         system = get_test_system()
+        # Make the system have a marginally-functional get_module
+
+        def fake_get_module(descriptor):
+            """
+            A fake module-maker.
+            """
+            if descriptor.name == 'capa':
+                return capa_module
+        system.get_module = fake_get_module
+
         module = CrowdsourceHinterModule(system, descriptor, model_data)
 
         return module
 
+    @staticmethod
+    def setup_formula_response(module):
+        """
+        Adds additional mock methods to the module, so that we can test
+        formula responses.
+        """
+        # Do a bunch of monkey patching, to mock the lon-capa problem.
+        responder = MagicMock()
+        responder.randomize_variables = MagicMock(return_value=4)
+
+        def fake_hash_answers(answer, test_values):
+            """ A fake answer hasher """
+            if test_values == 4 and answer == 'x*y^2':
+                return 'good'
+            raise StudentInputError
+
+        responder.hash_answers = fake_hash_answers
+        lcp = MagicMock()
+        lcp.responders = {'responder0': responder}
+        module.get_display_items()[0].lcp = lcp
+        return module
+
 
 class VerticalWithModulesFactory(object):
     """
@@ -226,6 +270,44 @@ class CrowdsourceHinterTest(unittest.TestCase):
         self.assertTrue('Test numerical problem.' in out_html)
         self.assertTrue('Another test numerical problem.' in out_html)
 
+    def test_numerical_answer_to_str(self):
+        """
+        Tests the get request to string converter for numerical responses.
+        """
+        mock_module = CHModuleFactory.create()
+        get = {'response1': '4'}
+        parsed = mock_module.numerical_answer_to_str(get)
+        self.assertTrue(parsed == '4.0')
+
+    def test_formula_answer_to_str(self):
+        """
+        Tests the get request to string converter for formula responses.
+        """
+        mock_module = CHModuleFactory.create()
+        get = {'response1': 'x*y^2'}
+        parsed = mock_module.formula_answer_to_str(get)
+        self.assertTrue(parsed == 'x*y^2')
+
+    def test_formula_answer_signature(self):
+        """
+        Tests the answer signature generator for formula responses.
+        """
+        mock_module = CHModuleFactory.create()
+        mock_module = CHModuleFactory.setup_formula_response(mock_module)
+        answer = 'x*y^2'
+        out = mock_module.formula_answer_signature(answer)
+        self.assertTrue(out == 'good')
+
+    def test_formula_answer_signature_failure(self):
+        """
+        Makes sure that bad answer strings return None as a signature.
+        """
+        mock_module = CHModuleFactory.create()
+        mock_module = CHModuleFactory.setup_formula_response(mock_module)
+        answer = 'fish'
+        out = mock_module.formula_answer_signature(answer)
+        self.assertTrue(out is None)
+
     def test_gethint_0hint(self):
         """
         Someone asks for a hint, when there's no hint to give.
@@ -343,6 +425,44 @@ class CrowdsourceHinterTest(unittest.TestCase):
         self.assertTrue(['Best hint', 40] in dict_out['hint_and_votes'])
         self.assertTrue(['Another hint', 31] in dict_out['hint_and_votes'])
 
+    def test_vote_unparsable(self):
+        """
+        A user somehow votes for an unparsable answer.
+        Should return a friendly error.
+        (This is an unusual exception path - I don't know how it occurs,
+        except if you manually make a post request.  But, it seems to happen
+        occasionally.)
+        """
+        mock_module = CHModuleFactory.create()
+        # None means that the answer couldn't be parsed.
+        mock_module.answer_signature = lambda text: None
+        json_in = {'answer': 'fish', 'hint': 3, 'pk_list': '[]'}
+        dict_out = mock_module.tally_vote(json_in)
+        print dict_out
+        self.assertTrue(dict_out == {'error': 'Failure in voting!'})
+
+    def test_vote_nohint(self):
+        """
+        A user somehow votes for a hint that doesn't exist.
+        Should return a friendly error.
+        """
+        mock_module = CHModuleFactory.create()
+        json_in = {'answer': '24.0', 'hint': '25', 'pk_list': '[]'}
+        dict_out = mock_module.tally_vote(json_in)
+        self.assertTrue(dict_out == {'error': 'Failure in voting!'})
+
+    def test_vote_badpklist(self):
+        """
+        Some of the pk's specified in pk_list are invalid.
+        Should just skip those.
+        """
+        mock_module = CHModuleFactory.create()
+        json_in = {'answer': '24.0', 'hint': '0', 'pk_list': json.dumps([0, 12])}
+        hint_and_votes = mock_module.tally_vote(json_in)['hint_and_votes']
+        self.assertTrue(['Best hint', 41] in hint_and_votes)
+        self.assertTrue(len(hint_and_votes) == 1)
+
+
     def test_submithint_nopermission(self):
         """
         A user tries to submit a hint, but he has already voted.
@@ -399,6 +519,17 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module.submit_hint(json_in)
         self.assertTrue(mock_module.hints['29.0']['0'][0] == u'&lt;script&gt; alert(&quot;Trololo&quot;); &lt;/script&gt;')
 
+    def test_submithint_unparsable(self):
+        mock_module = CHModuleFactory.create()
+        mock_module.answer_signature = lambda text: None
+        json_in = {'answer': 'fish', 'hint': 'A hint'}
+        dict_out = mock_module.submit_hint(json_in)
+        print dict_out
+        print mock_module.hints
+        self.assertTrue('error' in dict_out)
+        self.assertTrue(None not in mock_module.hints)
+        self.assertTrue('fish' not in mock_module.hints)
+
     def test_template_gethint(self):
         """
         Test the templates for get_hint.
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 4f40113265..3ca1ce5330 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -137,6 +137,10 @@ What would you say to help someone who got this wrong answer?
     ${simple_message()}
 % endif
 
+% if op == "error":
+    ${error}
+% endif
+
 % if op == "vote":
     ${show_votes()}
 % endif

From 6b40c5cf132164d9615e353f04034285af9eece4 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Mon, 15 Jul 2013 15:59:58 -0400
Subject: [PATCH 07/28] Changed hint voting ui to show all hints on one page.

Fixed broken tests for hint manager.
---
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 45 ++++++++---
 .../js/src/crowdsource_hinter/display.coffee  |  5 +-
 .../xmodule/tests/test_crowdsource_hinter.py  | 26 +++++-
 common/templates/hinter_display.html          | 80 ++++++++++++-------
 lms/djangoapps/instructor/hint_manager.py     |  8 +-
 .../instructor/tests/test_hint_manager.py     | 23 +++++-
 6 files changed, 132 insertions(+), 55 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 5c5c869088..b82241bd08 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -18,6 +18,9 @@ from xblock.core import Scope, String, Integer, Boolean, Dict, List
 
 from capa.responsetypes import FormulaResponse, StudentInputError
 
+from calc import evaluator, UndefinedVariable
+from pyparsing import ParseException
+
 from django.utils.html import escape
 
 log = logging.getLogger(__name__)
@@ -85,8 +88,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             self.answer_signature = self.formula_answer_signature
         else:
             self.answer_to_str = self.numerical_answer_to_str
-            # Right now, numerical problems don't need special answer signature treatment.
-            self.answer_signature = lambda x: x
+            self.answer_signature = self.numerical_answer_signature
 
     def get_html(self):
         """
@@ -134,6 +136,17 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         """
         return str(answer.values()[0])
 
+    def numerical_answer_signature(self, answer):
+        """
+        Runs the answer string through the evaluator.  (This is because
+        symbolic expressions like sin(pi/12)*3 are allowed.)
+        """
+        try:
+            out = str(evaluator(dict(), dict(), answer))
+        except (UndefinedVariable, ParseException):
+            out = None
+        return out
+
     def formula_answer_signature(self, answer):
         """
         Converts a capa answer string (output of formula_answer_to_str)
@@ -200,7 +213,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             return
         # Make a signature of the answer, for formula responses.
         signature = self.answer_signature(answer)
-        if signature == None:
+        if signature is None:
             # Sometimes, signature conversion may fail.
             log.exception('Signature conversion failed: ' + str(answer))
             return
@@ -258,13 +271,21 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # be allowed to make one vote / submission, but he can choose which wrong answer
         # he wants to look at.
         answer_to_hints = {}    # answer_to_hints[answer text][hint pk] -> hint text
+        signature_to_ans = {}   # Lets us combine equivalent answers
+                                # Same mapping as the field, but local.
 
         # Go through each previous answer, and populate index_to_hints and index_to_answer.
         for i in xrange(len(self.previous_answers)):
             answer, hints_offered = self.previous_answers[i]
+            # Does this answer equal one of the ones offered already?
+            signature = self.answer_signature(answer)
+            if signature in signature_to_ans:
+                # Re-assign this answer text to the one we've seen already.
+                answer = signature_to_ans[signature]
+            else:
+                signature_to_ans[signature] = answer
             if answer not in answer_to_hints:
                 answer_to_hints[answer] = {}
-            signature = self.answer_signature(answer)
             if signature in self.hints:
                 # Go through each hint, and add to index_to_hints
                 for hint_id in hints_offered:
@@ -285,9 +306,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         `data` -- expected to have the following keys:
             'answer': text of answer we're voting on
             'hint': hint_pk
-            'pk_list': We will return a list of how many votes each hint has so far.
+            'pk_list': A list of [answer, pk] pairs, each of which representing a hint.
+                       We will return a list of how many votes each hint in the list has so far.
                        It's up to the browser to specify which hints to return vote counts for.
-                       Every pk listed here will have a hint count returned.
+                       
         Returns key 'hint_and_votes', a list of (hint_text, #votes) pairs.
         """
         if self.user_voted:
@@ -299,7 +321,6 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             log.exception('Failure in hinter tally_vote: Unable to parse answer: ' + ans)
             return {'error': 'Failure in voting!'}
         hint_pk = str(data['hint'])
-        pk_list = json.loads(data['pk_list'])
         # We use temp_dict because we need to do a direct write for the database to update.
         temp_dict = self.hints
         try:
@@ -313,12 +334,18 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         self.user_voted = True
 
         # Return a list of how many votes each hint got.
+        pk_list = json.loads(data['pk_list'])
         hint_and_votes = []
-        for vote_pk in pk_list:
+        for answer, vote_pk in pk_list:
+            signature = self.answer_signature(answer)
+            if signature is None:
+                log.exception('In hinter tally_vote, couldn\'t parse ' + answer)
+                continue
             try:
                 hint_and_votes.append(temp_dict[signature][str(vote_pk)])
             except KeyError:
-                log.exception('In hinter tally_vote: pk_list contains non-existant pk: ' + str(vote_pk))
+                log.exception('In hinter tally_vote, couldn\'t find: '
+                              + answer + ', ' + str(vote_pk))
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers.
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 2e4d0e2c3b..db7ccfaba0 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -48,9 +48,7 @@ class @Hinter
 
   vote: (eventObj) =>
     target = @$(eventObj.currentTarget)
-    parent_div = $('.previous-answer[data-answer="'+target.attr('data-answer')+'"]')
-    all_pks = parent_div.attr('data-all-pks')
-    console.debug(all_pks)
+    all_pks = @$('#pk-list').attr('data-pk-list')
     post_json = {'answer': target.attr('data-answer'), 'hint': target.data('hintno'), 'pk_list': all_pks}
     $.postWithPrefix "#{@url}/vote", post_json, (response) =>
       @render(response.contents)
@@ -58,7 +56,6 @@ class @Hinter
   submit_hint: (eventObj) =>
     target = @$(eventObj.currentTarget)
     textarea = $('.custom-hint[data-answer="'+target.attr('data-answer')+'"]')
-    console.debug(textarea)
     post_json = {'answer': target.attr('data-answer'), 'hint': @$(textarea).val()}
     $.postWithPrefix "#{@url}/submit_hint",post_json, (response) =>
       @render(response.contents)
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index b8a205e90e..844c73a990 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -288,6 +288,26 @@ class CrowdsourceHinterTest(unittest.TestCase):
         parsed = mock_module.formula_answer_to_str(get)
         self.assertTrue(parsed == 'x*y^2')
 
+    def test_numerical_answer_signature(self):
+        """
+        Tests answer signature generator for numerical responses.
+        """
+        mock_module = CHModuleFactory.create()
+        answer = '4*5+3'
+        signature = mock_module.numerical_answer_signature(answer)
+        print signature
+        self.assertTrue(signature == '23.0')
+
+    def test_numerical_answer_signature_failure(self):
+        """
+        Makes sure that unparsable numerical answers return None.
+        """
+        mock_module = CHModuleFactory.create()
+        answer = 'fish'
+        signature = mock_module.numerical_answer_signature(answer)
+        print signature
+        self.assertTrue(signature is None)
+
     def test_formula_answer_signature(self):
         """
         Tests the answer signature generator for formula responses.
@@ -406,7 +426,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         Should not change any vote tallies.
         """
         mock_module = CHModuleFactory.create(user_voted=True)
-        json_in = {'answer': '24.0', 'hint': 1, 'pk_list': json.dumps([1, 3])}
+        json_in = {'answer': '24.0', 'hint': 1, 'pk_list': json.dumps([['24.0', 1], ['24.0', 3]])}
         old_hints = copy.deepcopy(mock_module.hints)
         mock_module.tally_vote(json_in)
         self.assertTrue(mock_module.hints == old_hints)
@@ -418,7 +438,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         """
         mock_module = CHModuleFactory.create(
             previous_answers=[['24.0', [0, 3, None]]])
-        json_in = {'answer': '24.0', 'hint': 3, 'pk_list': json.dumps([0, 3])}
+        json_in = {'answer': '24.0', 'hint': 3, 'pk_list': json.dumps([['24.0', 0], ['24.0', 3]])}
         dict_out = mock_module.tally_vote(json_in)
         self.assertTrue(mock_module.hints['24.0']['0'][1] == 40)
         self.assertTrue(mock_module.hints['24.0']['3'][1] == 31)
@@ -457,7 +477,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         Should just skip those.
         """
         mock_module = CHModuleFactory.create()
-        json_in = {'answer': '24.0', 'hint': '0', 'pk_list': json.dumps([0, 12])}
+        json_in = {'answer': '24.0', 'hint': '0', 'pk_list': json.dumps([['24.0', 0], ['24.0', 12]])}
         hint_and_votes = mock_module.tally_vote(json_in)['hint_and_votes']
         self.assertTrue(['Best hint', 41] in hint_and_votes)
         self.assertTrue(len(hint_and_votes) == 1)
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 3ca1ce5330..b13dc83ea2 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -18,11 +18,6 @@
 </%def>
 
 <%def name="get_feedback()">
-    <p><em> Participation in the hinting system is strictly optional, and will not influence your grade. </em></p>
-    <p>
-    Help your classmates by writing hints for this problem. Start by picking one of your previous incorrect answers from below:
-    </p>
-
     <%
     def unspace(string):
         """
@@ -30,7 +25,44 @@
         removes spaces.
         """
         return ''.join(string.split())
+
+    # Make a list of all hints shown.  (This is fed back to the site as pk_list.)
+    # At the same time, determine whether any hints were shown at all.
+    # If the user never saw hints, don't ask him to vote.
+    import json
+    hints_exist = False
+    pk_list = []
+    for answer, pk_dict in answer_to_hints.items():
+        if len(pk_dict) > 0:
+            hints_exist = True
+        for pk, hint_text in pk_dict.items():
+            pk_list.append([answer, pk])
+    json_pk_list = json.dumps(pk_list)
     %>
+    % if hints_exist:
+        <p>
+        <em> Optional. </em> Help us improve our hints!  Which hint was most helpful to you?
+        </p>
+
+        <div id="pk-list" data-pk-list='${json_pk_list}' style="display:none"> </div>
+
+        % for answer, pk_dict in answer_to_hints.items():
+            % for hint_pk, hint_text in pk_dict.items():
+                <p>
+                <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
+                ${answer}: ${hint_text}
+                </p>
+            % endfor
+        % endfor
+
+        <p>
+        Don't like any of the hints above?  Please write your own, for one of your previous incorrect answers below:
+        </p>
+    % else:
+        <p>
+        <em> Optional. </em> Help us write hints for this problem!  Select one of your incorrect answers below:
+        </p>
+    % endif
 
     <div id="answer-tabs">
         <ul>
@@ -40,36 +72,22 @@
         </ul>
 
         % for answer, pk_dict in answer_to_hints.items():
-        <%
-        import json
-        all_pks = json.dumps(pk_dict.keys())
-        %>
-        <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}" data-all-pks='${all_pks}'>
-        <div class = "hint-inner-container">
-            % if len(pk_dict) > 0:
+            <%
+                import json
+                all_pks = json.dumps(pk_dict.keys())
+            %>
+            <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}" data-all-pks='${all_pks}'>
+            <div class = "hint-inner-container">
                 <p>
-                Which hint would be most effective to show a student who also got ${answer}?
+                What hint would you give a student who made the same mistake you did?  Please don't give away the answer.
                 </p>
-                % for hint_pk, hint_text in pk_dict.items():
-                    <p>
-                    <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
-                    ${hint_text}
-                    </p>
-                % endfor
-                <p>
-                Don't like any of the hints above?  You can also submit your own.
-                </p>
-            % endif
-            <p>
-            What hint would you give a student who made the same mistake you did?  Please don't give away the answer.
-            </p>
-            <textarea cols="50" class="custom-hint" data-answer="${answer}">
+                <textarea cols="50" class="custom-hint" data-answer="${answer}">
 What would you say to help someone who got this wrong answer?
 (Don't give away the answer, please.)
-            </textarea>
-            <br/><br/>
-            <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
-        </div></div>
+                </textarea>
+                <br/><br/>
+                <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
+            </div></div>
         % endfor
     </div>
 
diff --git a/lms/djangoapps/instructor/hint_manager.py b/lms/djangoapps/instructor/hint_manager.py
index b20cdc81e6..1f0d17ab03 100644
--- a/lms/djangoapps/instructor/hint_manager.py
+++ b/lms/djangoapps/instructor/hint_manager.py
@@ -16,8 +16,8 @@ from mitxmako.shortcuts import render_to_response, render_to_string
 
 from courseware.courses import get_course_with_access
 from courseware.models import XModuleContentField
-from courseware.module_render import get_module
-from courseware.model_data import ModelDataCache
+import courseware.module_render as module_render
+import courseware.model_data as model_data
 from xmodule.modulestore import Location
 from xmodule.modulestore.django import modulestore
 
@@ -232,8 +232,8 @@ def add_hint(request, course_id, field):
     # any alternative :(
     loc = Location(problem_id)
     descriptors = modulestore().get_items(loc)
-    m_d_c = ModelDataCache(descriptors, course_id, request.user)
-    hinter_module = get_module(request.user, request, loc, m_d_c, course_id)
+    m_d_c = model_data.ModelDataCache(descriptors, course_id, request.user)
+    hinter_module = module_render.get_module(request.user, request, loc, m_d_c, course_id)
     signature = hinter_module.answer_signature(answer)
     if signature is None:
         # Signature generation failed.
diff --git a/lms/djangoapps/instructor/tests/test_hint_manager.py b/lms/djangoapps/instructor/tests/test_hint_manager.py
index 456f8e0ed8..9e579ab997 100644
--- a/lms/djangoapps/instructor/tests/test_hint_manager.py
+++ b/lms/djangoapps/instructor/tests/test_hint_manager.py
@@ -2,6 +2,7 @@ import json
 
 from django.test.client import Client, RequestFactory
 from django.test.utils import override_settings
+from mock import MagicMock
 
 from courseware.models import XModuleContentField
 from courseware.tests.factories import ContentFactory
@@ -89,7 +90,7 @@ class HintManagerTest(ModuleStoreTestCase):
         out = view.get_hints(post, self.course_id, 'mod_queue')
         print out
         self.assertTrue(out['other_field'] == 'hints')
-        expected = {self.problem_id: [(u'2.0', {u'2': [u'Hint 2', 1]})]}
+        expected = {self.problem_id: [[u'2.0', u'2.0', {u'2': [u'Hint 2', 1]}]]}
         self.assertTrue(out['all_hints'] == expected)
 
     def test_gethints_other(self):
@@ -101,9 +102,9 @@ class HintManagerTest(ModuleStoreTestCase):
         out = view.get_hints(post, self.course_id, 'hints')
         print out
         self.assertTrue(out['other_field'] == 'mod_queue')
-        expected = {self.problem_id: [('1.0', {'1': ['Hint 1', 2],
-                                               '3': ['Hint 3', 12]}),
-                                      ('2.0', {'4': ['Hint 4', 3]})
+        expected = {self.problem_id: [['1.0', '1.0', {'1': ['Hint 1', 2],
+                                                      '3': ['Hint 3', 12]}],
+                                      ['2.0', '2.0', {'4': ['Hint 4', 3]}]
                                       ]}
         self.assertTrue(out['all_hints'] == expected)
 
@@ -137,16 +138,30 @@ class HintManagerTest(ModuleStoreTestCase):
         """
         Check that instructors can add new hints.
         """
+        # Because add_hint accesses the xmodule, this test requires a bunch
+        # of monkey patching.
+        import courseware.module_render as module_render
+        import courseware.model_data as model_data
+        hinter = MagicMock()
+        hinter.answer_signature = lambda string: string
+        module_render.get_module = MagicMock(return_value=hinter)
+        model_data.ModelDataCache = MagicMock(return_value=None)
+
         request = RequestFactory()
         post = request.post(self.url, {'field': 'mod_queue',
                                        'op': 'add hint',
                                        'problem': self.problem_id,
                                        'answer': '3.14',
                                        'hint': 'This is a new hint.'})
+        post.user = 'fake user'
         view.add_hint(post, self.course_id, 'mod_queue')
         problem_hints = XModuleContentField.objects.get(field_name='mod_queue', definition_id=self.problem_id).value
         self.assertTrue('3.14' in json.loads(problem_hints))
 
+        # Reload the things we monkey-patched.
+        reload(module_render)
+        reload(model_data)
+
     def test_approve(self):
         """
         Check that instructors can approve hints.  (Move them

From 4ee8111cf4a77229404716ad85eeb00995a0fbbc Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Tue, 16 Jul 2013 09:12:35 -0400
Subject: [PATCH 08/28] Fixed monkey-patching persistent state bug.

---
 .../lib/xmodule/xmodule/crowdsource_hinter.py  |  4 ++--
 .../xmodule/tests/test_crowdsource_hinter.py   | 18 +++++++++++++++---
 .../instructor/tests/test_hint_manager.py      | 16 ++++++----------
 3 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index b82241bd08..1d7cf954a4 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -126,7 +126,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         -Lon-capa dependent.
         -Assumes that the problem only has one part.
         """
-        return str(float(answer.values()[0]))
+        return str(answer.values()[0])
 
     def formula_answer_to_str(self, answer):
         """
@@ -207,7 +207,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         """
         try:
             answer = self.answer_to_str(data)
-        except ValueError:
+        except (ValueError, AttributeError):
             # Sometimes, we get an answer that's just not parsable.  Do nothing.
             log.exception('Answer not parsable: ' + str(data))
             return
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index 844c73a990..cc0634cb7d 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -277,7 +277,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create()
         get = {'response1': '4'}
         parsed = mock_module.numerical_answer_to_str(get)
-        self.assertTrue(parsed == '4.0')
+        self.assertTrue(parsed == '4')
 
     def test_formula_answer_to_str(self):
         """
@@ -342,12 +342,24 @@ class CrowdsourceHinterTest(unittest.TestCase):
 
     def test_gethint_unparsable(self):
         """
-        Someone submits a hint that cannot be parsed into a float.
+        Someone submits an answer that is in the wrong format.
         - The answer should not be added to previous_answers.
         """
         mock_module = CHModuleFactory.create()
         old_answers = copy.deepcopy(mock_module.previous_answers)
-        json_in = {'problem_name': 'fish'}
+        json_in = 'blah'
+        out = mock_module.get_hint(json_in)
+        self.assertTrue(out is None)
+        self.assertTrue(mock_module.previous_answers == old_answers)
+
+    def test_gethint_signature_error(self):
+        """
+        Someone submits an answer that cannot be calculated as a float.
+        Nothing should change.
+        """
+        mock_module = CHModuleFactory.create()
+        old_answers = copy.deepcopy(mock_module.previous_answers)
+        json_in = {'problem1': 'fish'}
         out = mock_module.get_hint(json_in)
         self.assertTrue(out is None)
         self.assertTrue(mock_module.previous_answers == old_answers)
diff --git a/lms/djangoapps/instructor/tests/test_hint_manager.py b/lms/djangoapps/instructor/tests/test_hint_manager.py
index 9e579ab997..e9387a8eef 100644
--- a/lms/djangoapps/instructor/tests/test_hint_manager.py
+++ b/lms/djangoapps/instructor/tests/test_hint_manager.py
@@ -2,7 +2,7 @@ import json
 
 from django.test.client import Client, RequestFactory
 from django.test.utils import override_settings
-from mock import MagicMock
+from mock import MagicMock, patch
 
 from courseware.models import XModuleContentField
 from courseware.tests.factories import ContentFactory
@@ -12,6 +12,8 @@ from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
+import unittest
+
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class HintManagerTest(ModuleStoreTestCase):
@@ -140,12 +142,8 @@ class HintManagerTest(ModuleStoreTestCase):
         """
         # Because add_hint accesses the xmodule, this test requires a bunch
         # of monkey patching.
-        import courseware.module_render as module_render
-        import courseware.model_data as model_data
         hinter = MagicMock()
         hinter.answer_signature = lambda string: string
-        module_render.get_module = MagicMock(return_value=hinter)
-        model_data.ModelDataCache = MagicMock(return_value=None)
 
         request = RequestFactory()
         post = request.post(self.url, {'field': 'mod_queue',
@@ -154,14 +152,12 @@ class HintManagerTest(ModuleStoreTestCase):
                                        'answer': '3.14',
                                        'hint': 'This is a new hint.'})
         post.user = 'fake user'
-        view.add_hint(post, self.course_id, 'mod_queue')
+        with patch('courseware.module_render.get_module', MagicMock(return_value=hinter)):
+            with patch('courseware.model_data.ModelDataCache', MagicMock(return_value=None)):
+                view.add_hint(post, self.course_id, 'mod_queue')
         problem_hints = XModuleContentField.objects.get(field_name='mod_queue', definition_id=self.problem_id).value
         self.assertTrue('3.14' in json.loads(problem_hints))
 
-        # Reload the things we monkey-patched.
-        reload(module_render)
-        reload(model_data)
-
     def test_approve(self):
         """
         Check that instructors can approve hints.  (Move them

From 8ce53ed8eb865f651d755245d554926a3583a7c2 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Wed, 17 Jul 2013 17:00:51 -0400
Subject: [PATCH 09/28] Got rid of answer signatures - these don't work with
 approximate answers at all.  Instead, implemented comparison-based hint
 matching.

Tests are broken, hint manager is probably broken.
---
 common/lib/capa/capa/responsetypes.py         |  39 ++++
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 196 ++++++++----------
 common/templates/hinter_display.html          |  24 +--
 3 files changed, 131 insertions(+), 128 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 47289aad51..5f2408a09e 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -917,6 +917,27 @@ class NumericalResponse(LoncapaResponse):
 
     # TODO: add check_hint_condition(self, hxml_set, student_answers)
 
+    def answer_compare(self, a, b):
+        """
+        Outside-facing function that lets us compare two numerical answers,
+        with this problem's tolerance.
+        """
+        return compare_with_tolerance(
+            evaluator(dict(), dict(), a),
+            evaluator(dict(), dict(), b),
+            self.tolerance
+        )
+
+    def validate_answer(self, answer):
+        """
+        Returns whether this answer is in a valid form.
+        """
+        try:
+            evaluator(dict(), dict(), answer)
+            return True
+        except StudentInputError:
+            return False
+
     def get_answers(self):
         return {self.answer_id: self.correct_answer}
 
@@ -1858,6 +1879,24 @@ class FormulaResponse(LoncapaResponse):
                 return "incorrect"
         return "correct"
 
+    def answer_compare(self, a, b):
+        """
+        An external interface for comparing whether a and b are equal.
+        """
+        internal_result = self.check_formula(a, b, self.samples)
+        return internal_result == "correct"
+
+    def validate_answer(self, answer):
+        """
+        Returns whether this answer is in a valid form.
+        """
+        var_dict_list = self.randomize_variables(self.samples)
+        try:
+            self.hash_answers(answer, var_dict_list)
+            return True
+        except StudentInputError:
+            return False
+
     def strip_dict(self, d):
         ''' Takes a dict. Returns an identical dict, with all non-word
         keys and all non-numeric values stripped out. All values also
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 1d7cf954a4..37f244cdba 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -42,18 +42,11 @@ class CrowdsourceHinterFields(object):
     mod_queue = Dict(help='A dictionary containing hints still awaiting approval', scope=Scope.content,
                      default={})
     hint_pk = Integer(help='Used to index hints.', scope=Scope.content, default=0)
-    # signature_to_ans maps an answer signature to an answer string that shows that answer in a
-    # human-readable form.
-    signature_to_ans = Dict(help='Maps a signature to a representative formula.', scope=Scope.content,
-                            default={})
-    # A list of dictionaries, each of which represents an n-dimenstional point that we plug into
-    # formulas.  Each dictionary maps variables to values, eg {'x': 5.1}.
-    formula_test_values = List(help='The values that we plug into formula responses', scope=Scope.content,
-                               default=[])
+
     # A list of previous answers this student made to this problem.
-    # Of the form [answer, [hint_pk_1, hint_pk_2, hint_pk_3]] for each problem.  hint_pk's are
-    # None if the hint was not given.
-    previous_answers = List(help='A list of previous submissions.', scope=Scope.user_state, default=[])
+    # Of the form [answer, [hint_pk_1, ...]] for each problem.
+    previous_answers = List(help='A list of hints viewed.', scope=Scope.user_state, default=[])
+    user_submissions = List(help='A list of previous submissions', scope=Scope.user_state, default=[])
     user_voted = Boolean(help='Specifies if the user has voted on this problem or not.',
                          scope=Scope.user_state, default=False)
 
@@ -82,13 +75,20 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
         # We need to know whether we are working with a FormulaResponse problem.
-        self.is_formula = (type(self.get_display_items()[0].lcp.responders.values()[0]) == FormulaResponse)
+        responder = self.get_display_items()[0].lcp.responders.values()[0]
+        self.is_formula = (type(responder) == FormulaResponse)
         if self.is_formula:
             self.answer_to_str = self.formula_answer_to_str
-            self.answer_signature = self.formula_answer_signature
         else:
             self.answer_to_str = self.numerical_answer_to_str
-            self.answer_signature = self.numerical_answer_signature
+        # answer_compare is expected to return whether its two inputs are close enough
+        # to be equal, or raise a StudentInputError if one of the inputs is malformatted.
+        try:
+            self.answer_compare = responder.answer_compare
+            self.validate_answer = responder.validate_answer
+        except AttributeError:
+            # This response type is not supported!
+            log.exception('Response type not supported for hinting: ' + str(responder))
 
     def get_html(self):
         """
@@ -136,38 +136,12 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         """
         return str(answer.values()[0])
 
-    def numerical_answer_signature(self, answer):
+    def get_matching_answers(self, answer):
         """
-        Runs the answer string through the evaluator.  (This is because
-        symbolic expressions like sin(pi/12)*3 are allowed.)
+        Look in self.hints, and find all answer keys that are "equal with tolerance"
+        to the input answer.
         """
-        try:
-            out = str(evaluator(dict(), dict(), answer))
-        except (UndefinedVariable, ParseException):
-            out = None
-        return out
-
-    def formula_answer_signature(self, answer):
-        """
-        Converts a capa answer string (output of formula_answer_to_str)
-        to a string unique to each formula equality class.
-        So, x^2 and x*x would have the same signature, which would differ
-        from the signature of 2*x^2.
-        """
-        responder = self.get_display_items()[0].lcp.responders.values()[0]
-        if self.formula_test_values == []:
-            # Make a set of test values, and save them.
-            self.formula_test_values = responder.randomize_variables(responder.samples)
-        try:
-            # TODO, maybe: add some rounding to signature generation, so that floating point
-            # errors don't make a difference.
-            out = str(responder.hash_answers(answer, self.formula_test_values))
-        except StudentInputError:
-            # I'm not sure what's the best thing to do here.  I'm returning
-            # None, for now, so that the calling function has a chance to catch
-            # the error without having to import StudentInputError.
-            return None
-        return out
+        return [key for key in self.hints if self.answer_compare(key, answer)]
 
     def handle_ajax(self, dispatch, data):
         """
@@ -211,47 +185,67 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             # Sometimes, we get an answer that's just not parsable.  Do nothing.
             log.exception('Answer not parsable: ' + str(data))
             return
-        # Make a signature of the answer, for formula responses.
-        signature = self.answer_signature(answer)
-        if signature is None:
-            # Sometimes, signature conversion may fail.
-            log.exception('Signature conversion failed: ' + str(answer))
-            return
+        if not self.validate_answer(answer):
+            # Answer is not in the right form.
+            log.exception('Answer not valid: ' + str(answer))
+        if answer not in self.user_submissions:
+            self.user_submissions += [answer]
         # Look for a hint to give.
         # Make a local copy of self.hints - this means we only need to do one json unpacking.
         # (This is because xblocks storage makes the following command a deep copy.)
         local_hints = self.hints
-        if (signature not in local_hints) or (len(local_hints[signature]) == 0):
+        # For all answers similar enough to our own, accumulate all hints together.
+        # Also track the original answer of each hint.
+        matching_answers = self.get_matching_answers(answer)
+        matching_hints = {}
+        for matching_answer in matching_answers:
+            temp_dict = local_hints[matching_answer]
+            for key, value in temp_dict.items():
+                # Each value now has hint, votes, matching_answer.
+                temp_dict[key] = value + [matching_answer]
+            matching_hints.update(local_hints[matching_answer])
+        # matching_hints now maps pk's to lists of [hint, votes, matching_answer]
+        if len(matching_hints) == 0:
             # No hints to give.  Return.
-            self.previous_answers += [[answer, [None, None, None]]]
             return
         # Get the top hint, plus two random hints.
-        n_hints = len(local_hints[signature])
-        best_hint_index = max(local_hints[signature], key=lambda key: local_hints[signature][key][1])
-        best_hint = local_hints[signature][best_hint_index][0]
-        if len(local_hints[signature]) == 1:
-            rand_hint_1 = ''
-            rand_hint_2 = ''
-            self.previous_answers += [[answer, [best_hint_index, None, None]]]
-        elif n_hints == 2:
-            best_hint = local_hints[signature].values()[0][0]
-            best_hint_index = local_hints[signature].keys()[0]
-            rand_hint_1 = local_hints[signature].values()[1][0]
-            hint_index_1 = local_hints[signature].keys()[1]
-            rand_hint_2 = ''
-            self.previous_answers += [[answer, [best_hint_index, hint_index_1, None]]]
-        else:
-            (hint_index_1, rand_hint_1), (hint_index_2, rand_hint_2) =\
-                random.sample(local_hints[signature].items(), 2)
-            rand_hint_1 = rand_hint_1[0]
-            rand_hint_2 = rand_hint_2[0]
-            self.previous_answers += [[answer, [best_hint_index, hint_index_1, hint_index_2]]]
-
-        return {'best_hint': best_hint,
-                'rand_hint_1': rand_hint_1,
-                'rand_hint_2': rand_hint_2,
+        n_hints = len(matching_hints)
+        hints = []
+        best_hint_index = max(matching_hints, key=lambda key: matching_hints[key][1])
+        hints.append(matching_hints[best_hint_index][0])
+        best_hint_answer = matching_hints[best_hint_index][2]
+        # The brackets surrounding the index are for backwards compatability purposes.
+        # (It used to be that each answer was paired with multiple hints in a list.)
+        self.previous_answers += [[best_hint_answer, [best_hint_index]]]
+        for i in xrange(min(2, n_hints-1)):
+            # Keep making random hints until we hit a target, or run out.
+            (hint_index, (rand_hint, votes, hint_answer)) =\
+                random.choice(matching_hints.items())
+            if rand_hint in hints:
+                # Don't show the same hint twice.  Try again.
+                i -= 1
+                continue
+            hints.append(rand_hint)
+            self.previous_answers += [[hint_index, [hint_answer]]]
+        return {'hints': hints,
                 'answer': answer}
 
+        # rand_hint_1 = ''
+        # rand_hint_2 = ''
+        # if n_hints == 2:
+        #     best_hint = matching_hints.values()[0][0]
+        #     best_hint_index = matching_hints.keys()[0]
+        #     rand_hint_1 = matching_hints.values()[1][0]
+        #     hint_index_1 = matching_hints.keys()[1]
+        #     rand_hint_2 = ''
+        #     self.previous_answers += [[answer, [best_hint_index, hint_index_1]]]
+        # else:
+        #     (hint_index_1, rand_hint_1), (hint_index_2, rand_hint_2) =\
+        #         random.sample(matching_hints.items(), 2)
+        #     rand_hint_1 = rand_hint_1[0]
+        #     rand_hint_2 = rand_hint_2[0]
+        #     self.previous_answers += [[answer, [best_hint_index, hint_index_1, hint_index_2]]]
+
     def get_feedback(self, data):
         """
         The student got it correct.  Ask him to vote on hints, or submit a hint.
@@ -271,32 +265,24 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # be allowed to make one vote / submission, but he can choose which wrong answer
         # he wants to look at.
         answer_to_hints = {}    # answer_to_hints[answer text][hint pk] -> hint text
-        signature_to_ans = {}   # Lets us combine equivalent answers
-                                # Same mapping as the field, but local.
 
         # Go through each previous answer, and populate index_to_hints and index_to_answer.
         for i in xrange(len(self.previous_answers)):
             answer, hints_offered = self.previous_answers[i]
-            # Does this answer equal one of the ones offered already?
-            signature = self.answer_signature(answer)
-            if signature in signature_to_ans:
-                # Re-assign this answer text to the one we've seen already.
-                answer = signature_to_ans[signature]
-            else:
-                signature_to_ans[signature] = answer
             if answer not in answer_to_hints:
                 answer_to_hints[answer] = {}
-            if signature in self.hints:
+            if answer in self.hints:
                 # Go through each hint, and add to index_to_hints
                 for hint_id in hints_offered:
                     if (hint_id is not None) and (hint_id not in answer_to_hints[answer]):
                         try:
-                            answer_to_hints[answer][hint_id] = self.hints[signature][str(hint_id)][0]
+                            answer_to_hints[answer][hint_id] = self.hints[answer][str(hint_id)][0]
                         except KeyError:
                             # Sometimes, the hint that a user saw will have been deleted by the instructor.
                             continue
 
-        return {'answer_to_hints': answer_to_hints}
+        return {'answer_to_hints': answer_to_hints,
+                'user_submissions': self.user_submissions}
 
     def tally_vote(self, data):
         """
@@ -315,8 +301,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         if self.user_voted:
             return {'error': 'Sorry, but you have already voted!'}
         ans = data['answer']
-        signature = self.answer_signature(ans)
-        if signature is None:
+        if not self.validate_answer(ans):
             # Uh oh.  Invalid answer.
             log.exception('Failure in hinter tally_vote: Unable to parse answer: ' + ans)
             return {'error': 'Failure in voting!'}
@@ -324,7 +309,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # We use temp_dict because we need to do a direct write for the database to update.
         temp_dict = self.hints
         try:
-            temp_dict[signature][hint_pk][1] += 1
+            temp_dict[ans][hint_pk][1] += 1
         except KeyError:
             log.exception('Failure in hinter tally_vote: User voted for non-existant hint: Answer=' +
                           ans + ' pk=' + hint_pk)
@@ -337,19 +322,19 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         pk_list = json.loads(data['pk_list'])
         hint_and_votes = []
         for answer, vote_pk in pk_list:
-            signature = self.answer_signature(answer)
-            if signature is None:
+            if not self.validate_answer(answer):
                 log.exception('In hinter tally_vote, couldn\'t parse ' + answer)
                 continue
             try:
-                hint_and_votes.append(temp_dict[signature][str(vote_pk)])
+                hint_and_votes.append(temp_dict[answer][str(vote_pk)])
             except KeyError:
                 log.exception('In hinter tally_vote, couldn\'t find: '
                               + answer + ', ' + str(vote_pk))
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
-        # Reset self.previous_answers.
+        # Reset self.previous_answers and user_submissions.
         self.previous_answers = []
+        self.user_submissions = []
         return {'hint_and_votes': hint_and_votes}
 
     def submit_hint(self, data):
@@ -365,8 +350,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Do html escaping.  Perhaps in the future do profanity filtering, etc. as well.
         hint = escape(data['hint'])
         answer = data['answer']
-        signature = self.answer_signature(answer)
-        if signature is None:
+        if not self.validate_answer(answer):
             log.exception('Failure in hinter submit_hint: Unable to parse answer: ' + answer)
             return {'error': 'Could not submit answer'}
         # Only allow a student to vote or submit a hint once.
@@ -379,12 +363,9 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         else:
             temp_dict = self.hints
         if answer in temp_dict:
-            temp_dict[signature][str(self.hint_pk)] = [hint, 1]     # With one vote (the user himself).
+            temp_dict[answer][str(self.hint_pk)] = [hint, 1]     # With one vote (the user himself).
         else:
-            temp_dict[signature] = {str(self.hint_pk): [hint, 1]}
-        # Add the signature to signature_to_ans, if it's not there yet.
-        # This allows instructors to see a human-readable answer that corresponds to each signature.
-        self.add_signature(signature, answer)
+            temp_dict[answer] = {str(self.hint_pk): [hint, 1]}
         self.hint_pk += 1
         if self.moderate == 'True':
             self.mod_queue = temp_dict
@@ -393,18 +374,9 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # Mark the user has having voted; reset previous_answers
         self.user_voted = True
         self.previous_answers = []
+        self.user_submissions = []
         return {'message': 'Thank you for your hint!'}
 
-    def add_signature(self, signature, answer):
-        """
-        Add a signature to self.signature_to_ans.  If the signature already
-        exists, do nothing.
-        """
-        if signature not in self.signature_to_ans:
-            local_sta = self.signature_to_ans
-            local_sta[signature] = answer
-            self.signature_to_ans = local_sta
-
 
 class CrowdsourceHinterDescriptor(CrowdsourceHinterFields, RawDescriptor):
     module_class = CrowdsourceHinterModule
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index b13dc83ea2..ebd98e09bd 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -3,18 +3,14 @@
 
 
 <%def name="get_hint()">
-    % if best_hint != '':
+    % if len(hints) > 0:
         <h4> Hints from students who made similar mistakes: </h4>
         <ul>
-        <li> ${best_hint} </li>
+        % for hint in hints:
+            <li> ${hint} </li>
+        % endfor
+        </ul>
     % endif
-    % if rand_hint_1 != '':
-        <li> ${rand_hint_1} </li>
-    % endif
-    % if rand_hint_2 != '':
-        <li> ${rand_hint_2} </li>
-    % endif
-    </ul>
 </%def>
 
 <%def name="get_feedback()">
@@ -66,17 +62,13 @@
 
     <div id="answer-tabs">
         <ul>
-        % for answer in answer_to_hints:
+        % for answer in user_submissions:
             <li><a href="#previous-answer-${unspace(answer)}"> ${answer} </a></li>
         % endfor
         </ul>
 
-        % for answer, pk_dict in answer_to_hints.items():
-            <%
-                import json
-                all_pks = json.dumps(pk_dict.keys())
-            %>
-            <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}" data-all-pks='${all_pks}'>
+        % for answer in user_submissions:
+            <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}">
             <div class = "hint-inner-container">
                 <p>
                 What hint would you give a student who made the same mistake you did?  Please don't give away the answer.

From d9517ea13e2cbb63f4c2203186bb108a3074e78f Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 18 Jul 2013 15:02:19 -0400
Subject: [PATCH 10/28] Fixed tests for removing hash access to hints.  Fixed
 instructor view for same.

---
 .../lib/xmodule/xmodule/crowdsource_hinter.py |  13 ++-
 .../xmodule/tests/test_crowdsource_hinter.py  | 109 ++++++------------
 lms/djangoapps/instructor/hint_manager.py     |  84 +++++---------
 .../instructor/tests/test_hint_manager.py     |  35 ++++--
 .../instructor/hint_manager_inner.html        |   4 +-
 5 files changed, 105 insertions(+), 140 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 37f244cdba..ebb07506cb 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -188,6 +188,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         if not self.validate_answer(answer):
             # Answer is not in the right form.
             log.exception('Answer not valid: ' + str(answer))
+            return
         if answer not in self.user_submissions:
             self.user_submissions += [answer]
         # Look for a hint to give.
@@ -219,12 +220,12 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         self.previous_answers += [[best_hint_answer, [best_hint_index]]]
         for i in xrange(min(2, n_hints-1)):
             # Keep making random hints until we hit a target, or run out.
-            (hint_index, (rand_hint, votes, hint_answer)) =\
-                random.choice(matching_hints.items())
-            if rand_hint in hints:
-                # Don't show the same hint twice.  Try again.
-                i -= 1
-                continue
+            go_on = False
+            while not go_on:
+                (hint_index, (rand_hint, votes, hint_answer)) =\
+                    random.choice(matching_hints.items())
+                if not rand_hint in hints:
+                    go_on = True
             hints.append(rand_hint)
             self.previous_answers += [[hint_index, [hint_answer]]]
         return {'hints': hints,
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index cc0634cb7d..15939f2679 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -55,6 +55,7 @@ class CHModuleFactory(object):
     @staticmethod
     def create(hints=None,
                previous_answers=None,
+               user_submissions=None,
                user_voted=None,
                moderate=None,
                mod_queue=None):
@@ -87,9 +88,14 @@ class CHModuleFactory(object):
         else:
             model_data['previous_answers'] = [
                 ['24.0', [0, 3, 4]],
-                ['29.0', [None, None, None]]
+                ['29.0', []]
             ]
 
+        if user_submissions is not None:
+            model_data['user_submissions'] = user_submissions
+        else:
+            model_data['user_submissions'] = ['24.0', '29.0']
+
         if user_voted is not None:
             model_data['user_voted'] = user_voted
 
@@ -104,7 +110,24 @@ class CHModuleFactory(object):
 
         # Make a fake capa module.
         capa_module = MagicMock()
-        capa_module.responders = {'responder0': MagicMock()}
+        capa_module.lcp = MagicMock()
+        responder = MagicMock()
+
+        def validate_answer(answer):
+            """ A mock answer validator - simulates a numerical response"""
+            try:
+                float(answer)
+                return True
+            except ValueError:
+                return False
+        responder.validate_answer = validate_answer
+
+        def answer_compare(a, b):
+            """ A fake answer comparer """
+            return a == b
+        responder.answer_compare = answer_compare
+
+        capa_module.lcp.responders = {'responder0': responder}
         capa_module.displayable_items = lambda: [capa_module]
 
         system = get_test_system()
@@ -122,28 +145,6 @@ class CHModuleFactory(object):
 
         return module
 
-    @staticmethod
-    def setup_formula_response(module):
-        """
-        Adds additional mock methods to the module, so that we can test
-        formula responses.
-        """
-        # Do a bunch of monkey patching, to mock the lon-capa problem.
-        responder = MagicMock()
-        responder.randomize_variables = MagicMock(return_value=4)
-
-        def fake_hash_answers(answer, test_values):
-            """ A fake answer hasher """
-            if test_values == 4 and answer == 'x*y^2':
-                return 'good'
-            raise StudentInputError
-
-        responder.hash_answers = fake_hash_answers
-        lcp = MagicMock()
-        lcp.responders = {'responder0': responder}
-        module.get_display_items()[0].lcp = lcp
-        return module
-
 
 class VerticalWithModulesFactory(object):
     """
@@ -288,46 +289,6 @@ class CrowdsourceHinterTest(unittest.TestCase):
         parsed = mock_module.formula_answer_to_str(get)
         self.assertTrue(parsed == 'x*y^2')
 
-    def test_numerical_answer_signature(self):
-        """
-        Tests answer signature generator for numerical responses.
-        """
-        mock_module = CHModuleFactory.create()
-        answer = '4*5+3'
-        signature = mock_module.numerical_answer_signature(answer)
-        print signature
-        self.assertTrue(signature == '23.0')
-
-    def test_numerical_answer_signature_failure(self):
-        """
-        Makes sure that unparsable numerical answers return None.
-        """
-        mock_module = CHModuleFactory.create()
-        answer = 'fish'
-        signature = mock_module.numerical_answer_signature(answer)
-        print signature
-        self.assertTrue(signature is None)
-
-    def test_formula_answer_signature(self):
-        """
-        Tests the answer signature generator for formula responses.
-        """
-        mock_module = CHModuleFactory.create()
-        mock_module = CHModuleFactory.setup_formula_response(mock_module)
-        answer = 'x*y^2'
-        out = mock_module.formula_answer_signature(answer)
-        self.assertTrue(out == 'good')
-
-    def test_formula_answer_signature_failure(self):
-        """
-        Makes sure that bad answer strings return None as a signature.
-        """
-        mock_module = CHModuleFactory.create()
-        mock_module = CHModuleFactory.setup_formula_response(mock_module)
-        answer = 'fish'
-        out = mock_module.formula_answer_signature(answer)
-        self.assertTrue(out is None)
-
     def test_gethint_0hint(self):
         """
         Someone asks for a hint, when there's no hint to give.
@@ -337,8 +298,9 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create()
         json_in = {'problem_name': '26.0'}
         out = mock_module.get_hint(json_in)
+        print mock_module.previous_answers
         self.assertTrue(out is None)
-        self.assertTrue(['26.0', [None, None, None]] in mock_module.previous_answers)
+        self.assertTrue('26.0' in mock_module.user_submissions)
 
     def test_gethint_unparsable(self):
         """
@@ -359,10 +321,13 @@ class CrowdsourceHinterTest(unittest.TestCase):
         """
         mock_module = CHModuleFactory.create()
         old_answers = copy.deepcopy(mock_module.previous_answers)
+        old_user_submissions = copy.deepcopy(mock_module.user_submissions)
         json_in = {'problem1': 'fish'}
         out = mock_module.get_hint(json_in)
         self.assertTrue(out is None)
         self.assertTrue(mock_module.previous_answers == old_answers)
+        self.assertTrue(mock_module.user_submissions == old_user_submissions)
+
 
     def test_gethint_1hint(self):
         """
@@ -372,7 +337,11 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create()
         json_in = {'problem_name': '25.0'}
         out = mock_module.get_hint(json_in)
-        self.assertTrue(out['best_hint'] == 'Really popular hint')
+        self.assertTrue('Really popular hint' in out['hints'])
+        # Also make sure that the input gets added to user_submissions,
+        # and that the hint is logged in previous_answers.
+        self.assertTrue('25.0' in mock_module.user_submissions)
+        self.assertTrue(['25.0', ['1']] in mock_module.previous_answers)
 
     def test_gethint_manyhints(self):
         """
@@ -385,9 +354,8 @@ class CrowdsourceHinterTest(unittest.TestCase):
         mock_module = CHModuleFactory.create()
         json_in = {'problem_name': '24.0'}
         out = mock_module.get_hint(json_in)
-        self.assertTrue(out['best_hint'] == 'Best hint')
-        self.assertTrue('rand_hint_1' in out)
-        self.assertTrue('rand_hint_2' in out)
+        self.assertTrue('Best hint' in out['hints'])
+        self.assertTrue(len(out['hints']) == 3)
 
     def test_getfeedback_0wronganswers(self):
         """
@@ -527,8 +495,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         # Make a hint request.
         json_in = {'problem name': '25.0'}
         out = mock_module.get_hint(json_in)
-        self.assertTrue((out['best_hint'] == 'This is a new hint.')
-                        or (out['rand_hint_1'] == 'This is a new hint.'))
+        self.assertTrue('This is a new hint.' in out['hints'])
 
     def test_submithint_moderate(self):
         """
diff --git a/lms/djangoapps/instructor/hint_manager.py b/lms/djangoapps/instructor/hint_manager.py
index 1f0d17ab03..3616445543 100644
--- a/lms/djangoapps/instructor/hint_manager.py
+++ b/lms/djangoapps/instructor/hint_manager.py
@@ -10,7 +10,6 @@ import re
 
 from django.http import HttpResponse, Http404
 from django_future.csrf import ensure_csrf_cookie
-from django.core.exceptions import ObjectDoesNotExist
 
 from mitxmako.shortcuts import render_to_response, render_to_string
 
@@ -114,27 +113,8 @@ def get_hints(request, course_id, field):
                 # Put all non-numerical answers first.
                 return float('-inf')
 
-        # Find the signature to answer converter for this problem.  Sometimes,
-        # it doesn't exist; just assume that the signatures are the answers.
-        try:
-            signature_to_ans = XModuleContentField.objects.get(
-                field_name='signature_to_ans',
-                definition_id__regex=chopped_id
-            )
-            signature_to_ans = json.loads(signature_to_ans.value)
-        except ObjectDoesNotExist:
-            signature_to_ans = {}
-
-        signatures_dict = json.loads(hints_by_problem.value)
-        unsorted = []
-        for signature, dict_of_hints in signatures_dict.items():
-            if signature in signature_to_ans:
-                ans_txt = signature_to_ans[signature]
-            else:   
-                ans_txt = signature
-            unsorted.append([signature, ans_txt, dict_of_hints])
-        # Answer list contains [signature, answer, dict_of_hints] sub-lists.
-        answer_list = sorted(unsorted, key=answer_sorter)
+        # Answer list contains [answer, dict_of_hints] pairs.
+        answer_list = sorted(json.loads(hints_by_problem.value).items(), key=answer_sorter)
         big_out_dict[hints_by_problem.definition_id] = answer_list
 
     render_dict = {'field': field,
@@ -165,7 +145,7 @@ def delete_hints(request, course_id, field):
     Deletes the hints specified.
 
     `request.POST` contains some fields keyed by integers.  Each such field contains a
-    [problem_defn_id, signature, pk] tuple.  These tuples specify the hints to be deleted.
+    [problem_defn_id, answer, pk] tuple.  These tuples specify the hints to be deleted.
 
     Example `request.POST`:
     {'op': 'delete_hints',
@@ -177,12 +157,12 @@ def delete_hints(request, course_id, field):
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, signature, pk = request.POST.getlist(key)
+        problem_id, answer, pk = request.POST.getlist(key)
         # Can be optimized - sort the delete list by problem_id, and load each problem
         # from the database only once.
         this_problem = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(this_problem.value)
-        del problem_dict[signature][pk]
+        del problem_dict[answer][pk]
         this_problem.value = json.dumps(problem_dict)
         this_problem.save()
 
@@ -191,18 +171,18 @@ def change_votes(request, course_id, field):
     """
     Updates the number of votes.
 
-    The numbered fields of `request.POST` contain [problem_id, signature, pk, new_votes] tuples.
+    The numbered fields of `request.POST` contain [problem_id, answer, pk, new_votes] tuples.
     - Very similar to `delete_hints`.  Is there a way to merge them?  Nah, too complicated.
     """
 
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, signature, pk, new_votes = request.POST.getlist(key)
+        problem_id, answer, pk, new_votes = request.POST.getlist(key)
         this_problem = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(this_problem.value)
-        # problem_dict[signature][pk] points to a [hint_text, #votes] pair.
-        problem_dict[signature][pk][1] = int(new_votes)
+        # problem_dict[answer][pk] points to a [hint_text, #votes] pair.
+        problem_dict[answer][pk][1] = int(new_votes)
         this_problem.value = json.dumps(problem_dict)
         this_problem.save()
 
@@ -214,13 +194,24 @@ def add_hint(request, course_id, field):
     field
     problem - The problem id
     answer - The answer to which a hint will be added
-           - Needs to be converted into signature first.
     hint - The text of the hint
     """
 
     problem_id = request.POST['problem']
     answer = request.POST['answer']
     hint_text = request.POST['hint']
+
+    # Validate the answer.  This requires initializing the xmodules, which
+    # is annoying.
+    loc = Location(problem_id)
+    descriptors = modulestore().get_items(loc)
+    m_d_c = model_data.ModelDataCache(descriptors, course_id, request.user)
+    hinter_module = module_render.get_module(request.user, request, loc, m_d_c, course_id)
+    if not hinter_module.validate_answer(answer):
+        # Invalid answer.  Don't add it to the database, or else the
+        # hinter will crash when we encounter it.
+        return 'Error - the answer you specified is not properly formatted: ' + str(answer)
+
     this_problem = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
 
     hint_pk_entry = XModuleContentField.objects.get(field_name='hint_pk', definition_id=problem_id)
@@ -228,23 +219,10 @@ def add_hint(request, course_id, field):
     hint_pk_entry.value = this_pk + 1
     hint_pk_entry.save()
 
-    # Make signature.  This is really annoying, but I don't see
-    # any alternative :(
-    loc = Location(problem_id)
-    descriptors = modulestore().get_items(loc)
-    m_d_c = model_data.ModelDataCache(descriptors, course_id, request.user)
-    hinter_module = module_render.get_module(request.user, request, loc, m_d_c, course_id)
-    signature = hinter_module.answer_signature(answer)
-    if signature is None:
-        # Signature generation failed.
-        # We should probably return an error message, too... working on that.
-        return 'Error - your answer could not be parsed as a formula expression.'
-    hinter_module.add_signature(signature, answer)
-
     problem_dict = json.loads(this_problem.value)
-    if signature not in problem_dict:
-        problem_dict[signature] = {}
-    problem_dict[signature][this_pk] = [hint_text, 1]
+    if answer not in problem_dict:
+        problem_dict[answer] = {}
+    problem_dict[answer][this_pk] = [hint_text, 1]
     this_problem.value = json.dumps(problem_dict)
     this_problem.save()
 
@@ -254,26 +232,26 @@ def approve(request, course_id, field):
     Approve a list of hints, moving them from the mod_queue to the real
     hint list.  POST:
     op, field
-    (some number) -> [problem, signature, pk]
+    (some number) -> [problem, answer, pk]
     """
 
     for key in request.POST:
         if key == 'op' or key == 'field':
             continue
-        problem_id, signature, pk = request.POST.getlist(key)
+        problem_id, answer, pk = request.POST.getlist(key)
         # Can be optimized - sort the delete list by problem_id, and load each problem
         # from the database only once.
         problem_in_mod = XModuleContentField.objects.get(field_name=field, definition_id=problem_id)
         problem_dict = json.loads(problem_in_mod.value)
-        hint_to_move = problem_dict[signature][pk]
-        del problem_dict[signature][pk]
+        hint_to_move = problem_dict[answer][pk]
+        del problem_dict[answer][pk]
         problem_in_mod.value = json.dumps(problem_dict)
         problem_in_mod.save()
 
         problem_in_hints = XModuleContentField.objects.get(field_name='hints', definition_id=problem_id)
         problem_dict = json.loads(problem_in_hints.value)
-        if signature not in problem_dict:
-            problem_dict[signature] = {}
-        problem_dict[signature][pk] = hint_to_move
+        if answer not in problem_dict:
+            problem_dict[answer] = {}
+        problem_dict[answer][pk] = hint_to_move
         problem_in_hints.value = json.dumps(problem_dict)
         problem_in_hints.save()
diff --git a/lms/djangoapps/instructor/tests/test_hint_manager.py b/lms/djangoapps/instructor/tests/test_hint_manager.py
index e9387a8eef..fae2e48bb4 100644
--- a/lms/djangoapps/instructor/tests/test_hint_manager.py
+++ b/lms/djangoapps/instructor/tests/test_hint_manager.py
@@ -2,7 +2,7 @@ import json
 
 from django.test.client import Client, RequestFactory
 from django.test.utils import override_settings
-from mock import MagicMock, patch
+from mock import patch, MagicMock
 
 from courseware.models import XModuleContentField
 from courseware.tests.factories import ContentFactory
@@ -12,8 +12,6 @@ from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
-import unittest
-
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class HintManagerTest(ModuleStoreTestCase):
@@ -92,7 +90,7 @@ class HintManagerTest(ModuleStoreTestCase):
         out = view.get_hints(post, self.course_id, 'mod_queue')
         print out
         self.assertTrue(out['other_field'] == 'hints')
-        expected = {self.problem_id: [[u'2.0', u'2.0', {u'2': [u'Hint 2', 1]}]]}
+        expected = {self.problem_id: [(u'2.0', {u'2': [u'Hint 2', 1]})]}
         self.assertTrue(out['all_hints'] == expected)
 
     def test_gethints_other(self):
@@ -104,9 +102,9 @@ class HintManagerTest(ModuleStoreTestCase):
         out = view.get_hints(post, self.course_id, 'hints')
         print out
         self.assertTrue(out['other_field'] == 'mod_queue')
-        expected = {self.problem_id: [['1.0', '1.0', {'1': ['Hint 1', 2],
-                                                      '3': ['Hint 3', 12]}],
-                                      ['2.0', '2.0', {'4': ['Hint 4', 3]}]
+        expected = {self.problem_id: [('1.0', {'1': ['Hint 1', 2],
+                                               '3': ['Hint 3', 12]}),
+                                      ('2.0', {'4': ['Hint 4', 3]})
                                       ]}
         self.assertTrue(out['all_hints'] == expected)
 
@@ -143,7 +141,7 @@ class HintManagerTest(ModuleStoreTestCase):
         # Because add_hint accesses the xmodule, this test requires a bunch
         # of monkey patching.
         hinter = MagicMock()
-        hinter.answer_signature = lambda string: string
+        hinter.validate_answer = lambda string: True
 
         request = RequestFactory()
         post = request.post(self.url, {'field': 'mod_queue',
@@ -158,6 +156,27 @@ class HintManagerTest(ModuleStoreTestCase):
         problem_hints = XModuleContentField.objects.get(field_name='mod_queue', definition_id=self.problem_id).value
         self.assertTrue('3.14' in json.loads(problem_hints))
 
+    def test_addbadhint(self):
+        """
+        Check that instructors cannot add hints with unparsable answers.
+        """
+        # Patching.
+        hinter = MagicMock()
+        hinter.validate_answer = lambda string: False
+
+        request = RequestFactory()
+        post = request.post(self.url, {'field': 'mod_queue',
+                                       'op': 'add hint',
+                                       'problem': self.problem_id,
+                                       'answer': 'fish',
+                                       'hint': 'This is a new hint.'})
+        post.user = 'fake user'
+        with patch('courseware.module_render.get_module', MagicMock(return_value=hinter)):
+            with patch('courseware.model_data.ModelDataCache', MagicMock(return_value=None)):
+                view.add_hint(post, self.course_id, 'mod_queue')
+        problem_hints = XModuleContentField.objects.get(field_name='mod_queue', definition_id=self.problem_id).value
+        self.assertTrue('fish' not in json.loads(problem_hints))
+
     def test_approve(self):
         """
         Check that instructors can approve hints.  (Move them
diff --git a/lms/templates/instructor/hint_manager_inner.html b/lms/templates/instructor/hint_manager_inner.html
index 3acf8102ac..45101be2f6 100644
--- a/lms/templates/instructor/hint_manager_inner.html
+++ b/lms/templates/instructor/hint_manager_inner.html
@@ -8,12 +8,12 @@ Switch to <a id="switch-fields" other-field="${other_field}">${other_field_label
 
 % for definition_id in all_hints:
     <h2> Problem: ${id_to_name[definition_id]} </h2>
-    % for signature, answer, hint_dict in all_hints[definition_id]:
+    % for answer, hint_dict in all_hints[definition_id]:
         % if len(hint_dict) > 0:
             <h4> Answer: ${answer} </h4><div style="background-color:#EEEEEE">
         % endif
         % for pk, hint in hint_dict.items():
-            <p data-problem="${definition_id}" data-pk="${pk}" data-answer="${signature}">
+            <p data-problem="${definition_id}" data-pk="${pk}" data-answer="${answer}">
                 <input class="hint-select" type="checkbox"/> ${hint[0]}
                 <br /> 
                 Votes: <input type="text" class="votes" value="${str(hint[1])}" style="font-size:12px; height:20px; width:50px"></input>

From e2aea75f1626b7407053cbd44905ba07bb4087c8 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 18 Jul 2013 15:39:01 -0400
Subject: [PATCH 11/28] Fixed a bug in recording hints shown.

Removed the answer display next to voting.  (This was deemed distracting.)
---
 common/lib/xmodule/xmodule/crowdsource_hinter.py | 3 +--
 common/templates/hinter_display.html             | 4 ++--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index ebb07506cb..147de956af 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -227,7 +227,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
                 if not rand_hint in hints:
                     go_on = True
             hints.append(rand_hint)
-            self.previous_answers += [[hint_index, [hint_answer]]]
+            self.previous_answers += [[hint_answer, [hint_index]]]
         return {'hints': hints,
                 'answer': answer}
 
@@ -281,7 +281,6 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
                         except KeyError:
                             # Sometimes, the hint that a user saw will have been deleted by the instructor.
                             continue
-
         return {'answer_to_hints': answer_to_hints,
                 'user_submissions': self.user_submissions}
 
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index ebd98e09bd..4050824c5b 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -46,7 +46,7 @@
             % for hint_pk, hint_text in pk_dict.items():
                 <p>
                 <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
-                ${answer}: ${hint_text}
+                ${hint_text}
                 </p>
             % endfor
         % endfor
@@ -71,7 +71,7 @@
             <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}">
             <div class = "hint-inner-container">
                 <p>
-                What hint would you give a student who made the same mistake you did?  Please don't give away the answer.
+                What hint would you give a student who also arrived at an answer of ${answer}?  Please don't give away the correct answer.
                 </p>
                 <textarea cols="50" class="custom-hint" data-answer="${answer}">
 What would you say to help someone who got this wrong answer?

From 544aa55e43b79d228f5000724571055796129b61 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 19 Jul 2013 10:10:47 -0400
Subject: [PATCH 12/28] Added comments to explain confusing field names in
 crowdsource_hinter.

Fixed some pep8 errors.
---
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 29 +++++--------------
 .../xmodule/tests/test_crowdsource_hinter.py  |  6 +---
 2 files changed, 9 insertions(+), 26 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 147de956af..09783de5fd 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -16,10 +16,9 @@ from xmodule.x_module import XModule
 from xmodule.raw_module import RawDescriptor
 from xblock.core import Scope, String, Integer, Boolean, Dict, List
 
-from capa.responsetypes import FormulaResponse, StudentInputError
+from capa.responsetypes import FormulaResponse
 
-from calc import evaluator, UndefinedVariable
-from pyparsing import ParseException
+from calc import UndefinedVariable
 
 from django.utils.html import escape
 
@@ -43,9 +42,13 @@ class CrowdsourceHinterFields(object):
                      default={})
     hint_pk = Integer(help='Used to index hints.', scope=Scope.content, default=0)
 
-    # A list of previous answers this student made to this problem.
+    # A list of previous hints that a student viewed.
     # Of the form [answer, [hint_pk_1, ...]] for each problem.
+    # Sorry about the variable name - I know it's confusing.
     previous_answers = List(help='A list of hints viewed.', scope=Scope.user_state, default=[])
+
+    # user_submissions actually contains a list of previous answers submitted.
+    # (Originally, preivous_answers did this job, hence the name confusion.)
     user_submissions = List(help='A list of previous submissions', scope=Scope.user_state, default=[])
     user_voted = Boolean(help='Specifies if the user has voted on this problem or not.',
                          scope=Scope.user_state, default=False)
@@ -231,22 +234,6 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         return {'hints': hints,
                 'answer': answer}
 
-        # rand_hint_1 = ''
-        # rand_hint_2 = ''
-        # if n_hints == 2:
-        #     best_hint = matching_hints.values()[0][0]
-        #     best_hint_index = matching_hints.keys()[0]
-        #     rand_hint_1 = matching_hints.values()[1][0]
-        #     hint_index_1 = matching_hints.keys()[1]
-        #     rand_hint_2 = ''
-        #     self.previous_answers += [[answer, [best_hint_index, hint_index_1]]]
-        # else:
-        #     (hint_index_1, rand_hint_1), (hint_index_2, rand_hint_2) =\
-        #         random.sample(matching_hints.items(), 2)
-        #     rand_hint_1 = rand_hint_1[0]
-        #     rand_hint_2 = rand_hint_2[0]
-        #     self.previous_answers += [[answer, [best_hint_index, hint_index_1, hint_index_2]]]
-
     def get_feedback(self, data):
         """
         The student got it correct.  Ask him to vote on hints, or submit a hint.
@@ -295,7 +282,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             'pk_list': A list of [answer, pk] pairs, each of which representing a hint.
                        We will return a list of how many votes each hint in the list has so far.
                        It's up to the browser to specify which hints to return vote counts for.
-                       
+
         Returns key 'hint_and_votes', a list of (hint_text, #votes) pairs.
         """
         if self.user_voted:
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index 15939f2679..efb9874401 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -9,8 +9,6 @@ import copy
 from xmodule.crowdsource_hinter import CrowdsourceHinterModule
 from xmodule.vertical_module import VerticalModule, VerticalDescriptor
 
-from capa.responsetypes import StudentInputError
-
 from . import get_test_system
 
 import json
@@ -328,7 +326,6 @@ class CrowdsourceHinterTest(unittest.TestCase):
         self.assertTrue(mock_module.previous_answers == old_answers)
         self.assertTrue(mock_module.user_submissions == old_user_submissions)
 
-
     def test_gethint_1hint(self):
         """
         Someone asks for a hint, with exactly one hint in the database.
@@ -462,7 +459,6 @@ class CrowdsourceHinterTest(unittest.TestCase):
         self.assertTrue(['Best hint', 41] in hint_and_votes)
         self.assertTrue(len(hint_and_votes) == 1)
 
-
     def test_submithint_nopermission(self):
         """
         A user tries to submit a hint, but he has already voted.
@@ -489,7 +485,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         A user submits a hint to an answer that has other hints
         already.
         """
-        mock_module = CHModuleFactory.create(previous_answers = [['25.0', [1, None, None]]])
+        mock_module = CHModuleFactory.create(previous_answers=[['25.0', [1, None, None]]])
         json_in = {'answer': '25.0', 'hint': 'This is a new hint.'}
         mock_module.submit_hint(json_in)
         # Make a hint request.

From eb5a90a3ed2203cdf8d08616a4e3f51f4b5548c5 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 19 Jul 2013 10:59:09 -0400
Subject: [PATCH 13/28] Added tests for validate_answer in response types.

---
 common/lib/capa/capa/responsetypes.py         |  2 +-
 .../lib/capa/capa/tests/test_responsetypes.py | 28 +++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 5f2408a09e..319ac2b26d 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -935,7 +935,7 @@ class NumericalResponse(LoncapaResponse):
         try:
             evaluator(dict(), dict(), answer)
             return True
-        except StudentInputError:
+        except (StudentInputError, UndefinedVariable):
             return False
 
     def get_answers(self):
diff --git a/common/lib/capa/capa/tests/test_responsetypes.py b/common/lib/capa/capa/tests/test_responsetypes.py
index fd056f884e..7b9c302591 100644
--- a/common/lib/capa/capa/tests/test_responsetypes.py
+++ b/common/lib/capa/capa/tests/test_responsetypes.py
@@ -496,6 +496,20 @@ class FormulaResponseTest(ResponseTest):
         input_dict = {'1_2_1': '1/0'}
         self.assertRaises(StudentInputError, problem.grade_answers, input_dict)
 
+    def test_validate_answer(self):
+        """
+        Makes sure that validate_answer works.
+        """
+        sample_dict = {'x': (1, 2)}
+        problem = self.build_problem(
+            sample_dict=sample_dict,
+            num_samples=10,
+            tolerance="1%",
+            answer="x"
+        )
+        self.assertTrue(problem.responders.values()[0].validate_answer('14*x'))
+        self.assertFalse(problem.responders.values()[0].validate_answer('3*y+2*x'))
+
 
 class StringResponseTest(ResponseTest):
     from capa.tests.response_xml_factory import StringResponseXMLFactory
@@ -915,6 +929,20 @@ class NumericalResponseTest(ResponseTest):
                 with self.assertRaisesRegexp(StudentInputError, msg_regex):
                     problem.grade_answers({'1_2_1': 'foobar'})
 
+    def test_answer_compare(self):
+        """Tests the answer compare function."""
+        problem = self.build_problem(answer="42")
+        responder = problem.responders.values()[0]
+        self.assertTrue(responder.answer_compare('48', '8*6'))
+        self.assertFalse(responder.answer_compare('48', '9*5'))
+
+    def test_validate_answer(self):
+        """Tests the answer validation function."""
+        problem = self.build_problem(answer="42")
+        responder = problem.responders.values()[0]
+        self.assertTrue(responder.validate_answer('23.5'))
+        self.assertFalse(responder.validate_answer('fish'))
+
 
 class CustomResponseTest(ResponseTest):
     from capa.tests.response_xml_factory import CustomResponseXMLFactory

From e6db6e9ea3acb798638368aa78397c75e54c56e8 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 19 Jul 2013 16:03:32 -0400
Subject: [PATCH 14/28] Fixed bug where user isn't asked to submit a hint
 unless he's seen a hint.

---
 common/lib/xmodule/xmodule/crowdsource_hinter.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 09783de5fd..20a41dad06 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -246,7 +246,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         """
         # The student got it right.
         # Did he submit at least one wrong answer?
-        if len(self.previous_answers) == 0:
+        if len(self.user_submissions) == 0:
             # No.  Nothing to do here.
             return
         # Make a hint-voting interface for each wrong answer.  The student will only

From d6715749dc92fa683ec5e496314268ebe0e25c50 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Mon, 22 Jul 2013 14:00:44 -0400
Subject: [PATCH 15/28] Addressed pull request comments.

Fixed broken tests.
---
 common/lib/capa/capa/responsetypes.py              |  9 +++++++--
 common/lib/capa/capa/tests/test_responsetypes.py   |  6 +++---
 common/lib/xmodule/xmodule/crowdsource_hinter.py   | 14 ++++++++------
 .../js/src/crowdsource_hinter/display.coffee       |  1 -
 .../xmodule/tests/test_crowdsource_hinter.py       |  7 ++++---
 common/templates/hinter_display.html               |  4 ++--
 6 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 319ac2b26d..10f90b0372 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -917,7 +917,7 @@ class NumericalResponse(LoncapaResponse):
 
     # TODO: add check_hint_condition(self, hxml_set, student_answers)
 
-    def answer_compare(self, a, b):
+    def compare_answer(self, a, b):
         """
         Outside-facing function that lets us compare two numerical answers,
         with this problem's tolerance.
@@ -1870,6 +1870,11 @@ class FormulaResponse(LoncapaResponse):
         return out
 
     def check_formula(self, expected, given, samples):
+        """
+        Given an expected answer string, a given (student-produced) answer
+        string, and a samples string, return whether the given answer is
+        "correct" or "incorrect".
+        """
         var_dict_list = self.randomize_variables(samples)
         student_result = self.hash_answers(given, var_dict_list)
         instructor_result = self.hash_answers(expected, var_dict_list)
@@ -1879,7 +1884,7 @@ class FormulaResponse(LoncapaResponse):
                 return "incorrect"
         return "correct"
 
-    def answer_compare(self, a, b):
+    def compare_answer(self, a, b):
         """
         An external interface for comparing whether a and b are equal.
         """
diff --git a/common/lib/capa/capa/tests/test_responsetypes.py b/common/lib/capa/capa/tests/test_responsetypes.py
index 7b9c302591..84c52669ea 100644
--- a/common/lib/capa/capa/tests/test_responsetypes.py
+++ b/common/lib/capa/capa/tests/test_responsetypes.py
@@ -929,12 +929,12 @@ class NumericalResponseTest(ResponseTest):
                 with self.assertRaisesRegexp(StudentInputError, msg_regex):
                     problem.grade_answers({'1_2_1': 'foobar'})
 
-    def test_answer_compare(self):
+    def test_compare_answer(self):
         """Tests the answer compare function."""
         problem = self.build_problem(answer="42")
         responder = problem.responders.values()[0]
-        self.assertTrue(responder.answer_compare('48', '8*6'))
-        self.assertFalse(responder.answer_compare('48', '9*5'))
+        self.assertTrue(responder.compare_answer('48', '8*6'))
+        self.assertFalse(responder.compare_answer('48', '9*5'))
 
     def test_validate_answer(self):
         """Tests the answer validation function."""
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 20a41dad06..d46e862241 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -18,8 +18,6 @@ from xblock.core import Scope, String, Integer, Boolean, Dict, List
 
 from capa.responsetypes import FormulaResponse
 
-from calc import UndefinedVariable
-
 from django.utils.html import escape
 
 log = logging.getLogger(__name__)
@@ -84,10 +82,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             self.answer_to_str = self.formula_answer_to_str
         else:
             self.answer_to_str = self.numerical_answer_to_str
-        # answer_compare is expected to return whether its two inputs are close enough
+        # compare_answer is expected to return whether its two inputs are close enough
         # to be equal, or raise a StudentInputError if one of the inputs is malformatted.
         try:
-            self.answer_compare = responder.answer_compare
+            self.compare_answer = responder.compare_answer
             self.validate_answer = responder.validate_answer
         except AttributeError:
             # This response type is not supported!
@@ -144,7 +142,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         Look in self.hints, and find all answer keys that are "equal with tolerance"
         to the input answer.
         """
-        return [key for key in self.hints if self.answer_compare(key, answer)]
+        return [key for key in self.hints if self.compare_answer(key, answer)]
 
     def handle_ajax(self, dispatch, data):
         """
@@ -182,6 +180,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             - 'rand_hint_1' and 'rand_hint_2' are two random hints to the answer in `data`.
             - 'answer' is the parsed answer that was submitted.
         """
+        # First, validate our inputs.
         try:
             answer = self.answer_to_str(data)
         except (ValueError, AttributeError):
@@ -194,7 +193,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             return
         if answer not in self.user_submissions:
             self.user_submissions += [answer]
-        # Look for a hint to give.
+
+        # Next, find all of the hints that could possibly go with this answer.
         # Make a local copy of self.hints - this means we only need to do one json unpacking.
         # (This is because xblocks storage makes the following command a deep copy.)
         local_hints = self.hints
@@ -209,6 +209,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
                 temp_dict[key] = value + [matching_answer]
             matching_hints.update(local_hints[matching_answer])
         # matching_hints now maps pk's to lists of [hint, votes, matching_answer]
+
+        # Finally, randomly choose a subset of matching_hints to actually show.
         if len(matching_hints) == 0:
             # No hints to give.  Return.
             return
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index db7ccfaba0..d973f9a564 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -33,7 +33,6 @@ class @Hinter
     return string.replace(/[!"#$%&'()*+,.\/:;<=>?@\[\\\]^`{|}~]/g, '\\$&')
 
   bind: =>
-    window.update_schematics()
     @$('input.vote').click @vote
     @$('input.submit-hint').click @submit_hint
     @$('.custom-hint').click @clear_default_text
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index efb9874401..d28d2ee06b 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -120,10 +120,10 @@ class CHModuleFactory(object):
                 return False
         responder.validate_answer = validate_answer
 
-        def answer_compare(a, b):
+        def compare_answer(a, b):
             """ A fake answer comparer """
             return a == b
-        responder.answer_compare = answer_compare
+        responder.compare_answer = compare_answer
 
         capa_module.lcp.responders = {'responder0': responder}
         capa_module.displayable_items = lambda: [capa_module]
@@ -359,9 +359,10 @@ class CrowdsourceHinterTest(unittest.TestCase):
         Someone has gotten the problem correct on the first try.
         Output should be empty.
         """
-        mock_module = CHModuleFactory.create(previous_answers=[])
+        mock_module = CHModuleFactory.create(previous_answers=[], user_submissions=[])
         json_in = {'problem_name': '42.5'}
         out = mock_module.get_feedback(json_in)
+        print out
         self.assertTrue(out is None)
 
     def test_getfeedback_1wronganswer_nohints(self):
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 4050824c5b..d8b020c0f6 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -15,12 +15,12 @@
 
 <%def name="get_feedback()">
     <%
-    def unspace(string):
+    def unspace(in_str):
         """
         HTML id's can't have spaces in them.  This little function
         removes spaces.
         """
-        return ''.join(string.split())
+        return ''.join(in_str.split())
 
     # Make a list of all hints shown.  (This is fed back to the site as pk_list.)
     # At the same time, determine whether any hints were shown at all.

From f3c3436f4185f35f2fe5a32f4e33c01db546028b Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Tue, 30 Jul 2013 14:56:09 -0400
Subject: [PATCH 16/28] Addressing more PR comments.  Fixed a test that broke
 when new code came in.

---
 common/lib/capa/capa/responsetypes.py         | 20 ++++++++++---------
 .../lib/xmodule/xmodule/crowdsource_hinter.py |  7 ++++++-
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 10f90b0372..182266c21a 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -1799,7 +1799,7 @@ class FormulaResponse(LoncapaResponse):
             self.correct_answer, given, self.samples)
         return CorrectMap(self.answer_id, correctness)
 
-    def hash_answers(self, answer, var_dict_list):
+    def tupleize_answers(self, answer, var_dict_list):
         """
         Takes in an answer and a list of dictionaries mapping variables to values.
         Each dictionary represents a test case for the answer.
@@ -1850,7 +1850,7 @@ class FormulaResponse(LoncapaResponse):
     def randomize_variables(self, samples):
         """
         Returns a list of dictionaries mapping variables to random values in range,
-        as expected by hash_answers.
+        as expected by tupleize_answers.
         """
         variables = samples.split('@')[0].split(',')
         numsamples = int(samples.split('@')[1].split('#')[1])
@@ -1876,13 +1876,15 @@ class FormulaResponse(LoncapaResponse):
         "correct" or "incorrect".
         """
         var_dict_list = self.randomize_variables(samples)
-        student_result = self.hash_answers(given, var_dict_list)
-        instructor_result = self.hash_answers(expected, var_dict_list)
+        student_result = self.tupleize_answers(given, var_dict_list)
+        instructor_result = self.tupleize_answers(expected, var_dict_list)
 
-        for i in xrange(len(instructor_result)):
-            if not compare_with_tolerance(student_result[i], instructor_result[i], self.tolerance):
-                return "incorrect"
-        return "correct"
+        correct = all(compare_with_tolerance(student, instructor, self.tolerance)
+                      for student, instructor in zip(student_result, instructor_result))
+        if correct:
+            return "correct"
+        else:
+            return "incorrect"
 
     def compare_answer(self, a, b):
         """
@@ -1897,7 +1899,7 @@ class FormulaResponse(LoncapaResponse):
         """
         var_dict_list = self.randomize_variables(self.samples)
         try:
-            self.hash_answers(answer, var_dict_list)
+            self.tupleize_answers(answer, var_dict_list)
             return True
         except StudentInputError:
             return False
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index d46e862241..74b5f7b36e 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -76,7 +76,12 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
     def __init__(self, *args, **kwargs):
         XModule.__init__(self, *args, **kwargs)
         # We need to know whether we are working with a FormulaResponse problem.
-        responder = self.get_display_items()[0].lcp.responders.values()[0]
+        try:
+            responder = self.get_display_items()[0].lcp.responders.values()[0]
+        except (IndexError, AttributeError):
+            log.exception('Unable to find a capa problem child.')
+            return
+
         self.is_formula = (type(responder) == FormulaResponse)
         if self.is_formula:
             self.answer_to_str = self.formula_answer_to_str

From 64c91cf2391b2aabf82a7646cda8d45755ede99f Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Wed, 31 Jul 2013 15:17:18 -0400
Subject: [PATCH 17/28] UX improvements to hinting.  Interface is now less
 cluttered.

Hint submission is hidden behind a link, if there are hints to vote on.
---
 .../js/src/crowdsource_hinter/display.coffee  | 20 ++++---
 common/templates/hinter_display.html          | 54 ++++++++++---------
 2 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index d973f9a564..a1dc35a604 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -37,13 +37,14 @@ class @Hinter
     @$('input.submit-hint').click @submit_hint
     @$('.custom-hint').click @clear_default_text
     @$('#answer-tabs').tabs({active: 0})
-    @$('.expand-goodhint').click @expand_goodhint
+    @$('.expand').click @expand
 
-  expand_goodhint: =>
-    if @$('.goodhint').css('display') == 'none'
-      @$('.goodhint').css('display', 'block')
+  expand: (eventObj) =>
+    target = @$('#' + @$(eventObj.currentTarget).data('target'))
+    if @$(target).css('display') == 'none'
+      @$(target).css('display', 'block')
     else
-      @$('.goodhint').css('display', 'none')
+      @$(target).css('display', 'none')
 
   vote: (eventObj) =>
     target = @$(eventObj.currentTarget)
@@ -53,9 +54,12 @@ class @Hinter
       @render(response.contents)
 
   submit_hint: (eventObj) =>
-    target = @$(eventObj.currentTarget)
-    textarea = $('.custom-hint[data-answer="'+target.attr('data-answer')+'"]')
-    post_json = {'answer': target.attr('data-answer'), 'hint': @$(textarea).val()}
+    textarea = $('.custom-hint')
+    answer = $('input:radio[name=answer-select]:checked').val()
+    if answer == undefined
+      # The user didn't choose an answer.  Do nothing.
+      return
+    post_json = {'answer': answer, 'hint': textarea.val()}
     $.postWithPrefix "#{@url}/submit_hint",post_json, (response) =>
       @render(response.contents)
 
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index d8b020c0f6..8fd219e847 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -52,39 +52,35 @@
         % endfor
 
         <p>
-        Don't like any of the hints above?  Please write your own, for one of your previous incorrect answers below:
-        </p>
+        Don't like any of the hints above? 
+        <a class="expand" data-target="hint-submission-div" href="javascript:void(0);">
+          Write your own!
+        </a></p>
+
+        <div id="hint-submission-div" style="display:none">
     % else:
         <p>
-        <em> Optional. </em> Help us write hints for this problem!  Select one of your incorrect answers below:
+          <em> Optional. </em> Help us write hints for this problem!  Think about how you would help
+          another student who made the same mistake that you did.
         </p>
     % endif
 
-    <div id="answer-tabs">
-        <ul>
-        % for answer in user_submissions:
-            <li><a href="#previous-answer-${unspace(answer)}"> ${answer} </a></li>
-        % endfor
-        </ul>
+    <p>
+      Choose the incorrect answer for which you want to write a hint:
+      <br />
+      % for answer in user_submissions:
+          <input type="radio" name="answer-select" value="${answer}"> ${answer} </input><br />
+      % endfor
+    </p>
 
-        % for answer in user_submissions:
-            <div class = "previous-answer" id="previous-answer-${unspace(answer)}" data-answer="${answer}">
-            <div class = "hint-inner-container">
-                <p>
-                What hint would you give a student who also arrived at an answer of ${answer}?  Please don't give away the correct answer.
-                </p>
-                <textarea cols="50" class="custom-hint" data-answer="${answer}">
-What would you say to help someone who got this wrong answer?
-(Don't give away the answer, please.)
-                </textarea>
-                <br/><br/>
-                <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
-            </div></div>
-        % endfor
-    </div>
+    <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
+Write your hint here.  Please don't give away the correct answer.
+    </textarea>
+    <br/><br/>
+    <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
 
-    <p>Read about <a class="expand-goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
-    <div class="goodhint" style="display:none">
+    <p>Read about <a class="expand" data-target="goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
+    <div id="goodhint" style="display:none">
       <h4>What makes a good hint?</h4>
 
       <p>It depends on the type of problem you ran into. For stupid errors --
@@ -114,6 +110,12 @@ What would you say to help someone who got this wrong answer?
       <p>
         <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
       </p>    </div>
+    ## Close out the text-hiding div.  The text-hiding div only exists if there
+    ## were hints for the student to vote on.
+    % if hints_exist:
+      </div>
+    % endif
+
 
 </%def>
 

From 7c93b45d0c0a7c2a0bc1d131593fe11258c028d2 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Wed, 31 Jul 2013 17:13:32 -0400
Subject: [PATCH 18/28] Added wizard / slideshow style hint collection script.

Still requires a little polishing, I think.
---
 .../js/src/crowdsource_hinter/display.coffee  |  32 +++++-
 common/templates/hinter_display.html          | 101 +++++++++++-------
 2 files changed, 87 insertions(+), 46 deletions(-)

diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index a1dc35a604..34956603c6 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -36,8 +36,9 @@ class @Hinter
     @$('input.vote').click @vote
     @$('input.submit-hint').click @submit_hint
     @$('.custom-hint').click @clear_default_text
-    @$('#answer-tabs').tabs({active: 0})
     @$('.expand').click @expand
+    @$('.wizard-link').click @wizard_link_handle
+    @$('.answer-choice').click @answer_choice_handle
 
   expand: (eventObj) =>
     target = @$('#' + @$(eventObj.currentTarget).data('target'))
@@ -55,11 +56,10 @@ class @Hinter
 
   submit_hint: (eventObj) =>
     textarea = $('.custom-hint')
-    answer = $('input:radio[name=answer-select]:checked').val()
-    if answer == undefined
-      # The user didn't choose an answer.  Do nothing.
+    if @answer == ''
+      # The user didn't choose an answer, somehow.  Do nothing.
       return
-    post_json = {'answer': answer, 'hint': textarea.val()}
+    post_json = {'answer': @answer, 'hint': textarea.val()}
     $.postWithPrefix "#{@url}/submit_hint",post_json, (response) =>
       @render(response.contents)
 
@@ -69,6 +69,15 @@ class @Hinter
       target.val('')
       target.data('cleared', true)
 
+  wizard_link_handle: (eventObj) =>
+    target = @$(eventObj.currentTarget)
+    @go_to(target.attr('dest'))
+
+  answer_choice_handle: (eventObj) =>
+    @answer = @$(eventObj.target).attr('value')
+    @$('#blank-answer').html(@answer)
+    @go_to('p3')
+
   render: (content) ->
     if content
       # Trim leading and trailing whitespace
@@ -82,3 +91,16 @@ class @Hinter
       @$('#previous-answer-0').css('display', 'inline')
     else
       @el.hide()
+    # Initialize the answer choice - remembers which answer the user picked on
+    # p2 when he submits a hint on p3.
+    @answer = ''
+    # Make the correct wizard view show up.
+    hints_exist = @$('#hints-exist').html() == 'True'
+    if hints_exist
+      @go_to('p1')
+    else
+      @go_to('p2')
+
+  go_to: (view_id) ->
+    $('.wizard-view').css('display', 'none')
+    $('#' + view_id).css('display', 'block')
\ No newline at end of file
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 8fd219e847..0f350083de 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -34,50 +34,71 @@
         for pk, hint_text in pk_dict.items():
             pk_list.append([answer, pk])
     json_pk_list = json.dumps(pk_list)
-    %>
-    % if hints_exist:
-        <p>
-        <em> Optional. </em> Help us improve our hints!  Which hint was most helpful to you?
-        </p>
+  %>
 
-        <div id="pk-list" data-pk-list='${json_pk_list}' style="display:none"> </div>
-
-        % for answer, pk_dict in answer_to_hints.items():
-            % for hint_pk, hint_text in pk_dict.items():
-                <p>
-                <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
-                ${hint_text}
-                </p>
-            % endfor
-        % endfor
-
-        <p>
-        Don't like any of the hints above? 
-        <a class="expand" data-target="hint-submission-div" href="javascript:void(0);">
-          Write your own!
-        </a></p>
-
-        <div id="hint-submission-div" style="display:none">
-    % else:
-        <p>
-          <em> Optional. </em> Help us write hints for this problem!  Think about how you would help
-          another student who made the same mistake that you did.
-        </p>
-    % endif
+  <!-- Tells coffeescript whether there are hints to show. -->
+  <span id="hints-exist" style="display:none">${hints_exist}</span>
 
+  <div class="wizard-view" id="p1">
     <p>
-      Choose the incorrect answer for which you want to write a hint:
-      <br />
-      % for answer in user_submissions:
-          <input type="radio" name="answer-select" value="${answer}"> ${answer} </input><br />
-      % endfor
+    <em> Optional. </em> Help us improve our hints!  Which hint was most helpful to you?
     </p>
 
+    <div id="pk-list" data-pk-list='${json_pk_list}' style="display:none"> </div>
+
+    % for answer, pk_dict in answer_to_hints.items():
+        % for hint_pk, hint_text in pk_dict.items():
+            <p>
+            <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
+            ${hint_text}
+            </p>
+        % endfor
+    % endfor
+
+    <p>
+    Don't like any of the hints above? 
+    <a class="wizard-link" dest="p2" href="javascript: void(0);">
+      Write your own!
+    </a></p>
+  </div>
+
+  <div class="wizard-view" id="p2">
+    % if hints_exist:
+      <p>
+      Choose the incorrect answer for which you want to write a hint:
+      </p>
+    % else:
+    <p>
+      <em>Optional.</em>  Help other students by submitting a hint!  Pick one of your previous
+      answers for which you would like to write a hint:
+    </p>
+    % endif
+    % for answer in user_submissions:
+        <a class="answer-choice" href="javascript: void(0)" value="${answer}">${answer}</a><br />
+    % endfor
+    % if hints_exist:
+      <br />
+      <p><a class="wizard-link" dest="p1" href="javascript: void(0);">
+        Back to voting.
+      </a></p>
+    % endif
+
+  </div>
+
+  <div class="wizard-view" id="p3">
+
+    <p>
+      Write a hint for other students who get the wrong answer of <span id="blank-answer"></span>.
+      <br />
+      <a class="wizard-link" dest="p2" href="javascript: void(0);">
+        Choose a different answer.
+      </a>
+    </p>
     <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
 Write your hint here.  Please don't give away the correct answer.
     </textarea>
     <br/><br/>
-    <input class="submit-hint" data-answer="${answer}" type="button" value="submit">
+    <input class="submit-hint" data-answer="${answer}" type="button" value="Submit">
 
     <p>Read about <a class="expand" data-target="goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
     <div id="goodhint" style="display:none">
@@ -109,12 +130,10 @@ Write your hint here.  Please don't give away the correct answer.
 
       <p>
         <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
-      </p>    </div>
-    ## Close out the text-hiding div.  The text-hiding div only exists if there
-    ## were hints for the student to vote on.
-    % if hints_exist:
-      </div>
-    % endif
+      </p>
+    </div>
+  </div>
+
 
 
 </%def>

From 35a8e9be326dab1ca27cc80160e0a29319f62653 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 1 Aug 2013 09:40:49 -0400
Subject: [PATCH 19/28] Some fixes on hint ui.

---
 common/templates/hinter_display.html | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 0f350083de..a7f2eafd1c 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -78,9 +78,7 @@
     % endfor
     % if hints_exist:
       <br />
-      <p><a class="wizard-link" dest="p1" href="javascript: void(0);">
-        Back to voting.
-      </a></p>
+      <a href="javascript: void(0);" class="wizard-link" dest="p1"> Back </a>
     % endif
 
   </div>
@@ -89,17 +87,7 @@
 
     <p>
       Write a hint for other students who get the wrong answer of <span id="blank-answer"></span>.
-      <br />
-      <a class="wizard-link" dest="p2" href="javascript: void(0);">
-        Choose a different answer.
-      </a>
     </p>
-    <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
-Write your hint here.  Please don't give away the correct answer.
-    </textarea>
-    <br/><br/>
-    <input class="submit-hint" data-answer="${answer}" type="button" value="Submit">
-
     <p>Read about <a class="expand" data-target="goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
     <div id="goodhint" style="display:none">
       <h4>What makes a good hint?</h4>
@@ -132,6 +120,14 @@ Write your hint here.  Please don't give away the correct answer.
         <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
       </p>
     </div>
+
+    <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
+Write your hint here.  Please don't give away the correct answer.
+    </textarea>
+    <br /><br />
+    <input class="submit-hint" data-answer="${answer}" type="button" value="Submit">
+    <br /><br />
+    <a href="javascript: void(0);" class="wizard-link" dest="p2"> Back </a>
   </div>
 
 

From 2d1c9158d885fee77e35146f5588cb931b6d3704 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 1 Aug 2013 14:52:37 -0400
Subject: [PATCH 20/28] Added fancy sliding transitions into hint collection
 page.

---
 .../css/crowdsource_hinter/display.scss       |  71 +++-----
 .../js/src/crowdsource_hinter/display.coffee  |  36 +++-
 common/templates/hinter_display.html          | 170 +++++++++---------
 3 files changed, 143 insertions(+), 134 deletions(-)

diff --git a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
index c1d7b1f048..ce40d10b53 100644
--- a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
+++ b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
@@ -7,52 +7,6 @@
   background: rgb(253, 248, 235);
 }
 
-#answer-tabs {
-  background: #FFFFFF;
-  border: none;
-  margin-bottom: 20px;
-  padding-bottom: 20px;
-}
-
-#answer-tabs .ui-widget-header {
-  border-bottom: 1px solid #DCDCDC;
-  background: #FDF8EB;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-default {
-  border: 1px solid #DCDCDC;
-  background: #E6E6E3;
-  margin-bottom: 0px;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-default:hover {
-  background: #FFFFFF;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-active:hover {
-  background: #FFFFFF;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-active {
-  border: 1px solid #DCDCDC;
-  background: #FFFFFF;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-active a {
-  color: #222222;
-  background: #FFFFFF;
-}
-
-#answer-tabs .ui-tabs-nav .ui-state-default a:hover {
-  color: #222222;
-  background: #FFFFFF;
-}
-
-#answer-tabs .custom-hint {
-  height: 100px;
-  width: 100%;
-}
-
 .hint-inner-container {
   padding-left: 15px;
   padding-right: 15px;
@@ -63,3 +17,28 @@
   padding-top: 0px !important;
   padding-bottom: 0px !important;
 }
+
+.wizard-view {
+  float: left;
+  width: 800px;
+}
+
+.wizard-container {
+  width: 3000px;
+
+  -webkit-transition:all 1.0s ease-in-out;
+  -moz-transition:all 1.0s ease-in-out;
+  -o-transition:all 1.0s ease-in-out;
+  transition:all 1.0s ease-in-out;
+}
+
+.wizard-viewbox {
+  width: 790px;
+  overflow: hidden;
+  position: relative;
+}
+
+.bottom {
+  position: absolute;
+  bottom: 0;
+}
\ No newline at end of file
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 34956603c6..3ecf73a0dc 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -41,13 +41,17 @@ class @Hinter
     @$('.answer-choice').click @answer_choice_handle
 
   expand: (eventObj) =>
+    # Expand a hidden div.
     target = @$('#' + @$(eventObj.currentTarget).data('target'))
     if @$(target).css('display') == 'none'
       @$(target).css('display', 'block')
     else
       @$(target).css('display', 'none')
+    # Fix positioning errors with the bottom class.
+    @$('.bottom').removeClass('bottom').addClass('bottom')
 
   vote: (eventObj) =>
+    # Make an ajax request with the user's vote.
     target = @$(eventObj.currentTarget)
     all_pks = @$('#pk-list').attr('data-pk-list')
     post_json = {'answer': target.attr('data-answer'), 'hint': target.data('hintno'), 'pk_list': all_pks}
@@ -55,6 +59,7 @@ class @Hinter
       @render(response.contents)
 
   submit_hint: (eventObj) =>
+    # Make an ajax request with the user's new hint.
     textarea = $('.custom-hint')
     if @answer == ''
       # The user didn't choose an answer, somehow.  Do nothing.
@@ -64,21 +69,25 @@ class @Hinter
       @render(response.contents)
 
   clear_default_text: (eventObj) =>
+    # Remove placeholder text in the hint submission textbox.
     target = @$(eventObj.currentTarget)
     if target.data('cleared') == undefined
       target.val('')
       target.data('cleared', true)
 
   wizard_link_handle: (eventObj) =>
+    # Move to another wizard view, based on the link that the user clicked.
     target = @$(eventObj.currentTarget)
     @go_to(target.attr('dest'))
 
   answer_choice_handle: (eventObj) =>
+    # A special case of wizard_link_handle - we need to track a state variable,
+    # the answer that the user chose.
     @answer = @$(eventObj.target).attr('value')
     @$('#blank-answer').html(@answer)
     @go_to('p3')
 
-  render: (content) ->
+  render: (content) =>
     if content
       # Trim leading and trailing whitespace
       content = content.replace /^\s+|\s+$/g, ""
@@ -94,6 +103,13 @@ class @Hinter
     # Initialize the answer choice - remembers which answer the user picked on
     # p2 when he submits a hint on p3.
     @answer = ''
+    # Determine whether the browser supports CSS3 transforms.
+    styles = document.body.style
+    if styles.WebkitTransform == '' or styles.transform == ''
+      @go_to = @transform_go_to
+    else
+      @go_to = @legacy_go_to
+
     # Make the correct wizard view show up.
     hints_exist = @$('#hints-exist').html() == 'True'
     if hints_exist
@@ -101,6 +117,18 @@ class @Hinter
     else
       @go_to('p2')
 
-  go_to: (view_id) ->
-    $('.wizard-view').css('display', 'none')
-    $('#' + view_id).css('display', 'block')
\ No newline at end of file
+  transform_go_to: (view_id) ->
+    # Switch wizard views using sliding transitions.
+    id_to_index = {
+      'p1': 0,
+      'p2': 1,
+      'p3': 2,
+    }
+    translate_string = 'translateX(' +id_to_index[view_id] * -1 * parseInt($('#' + view_id).css('width'), 10) + 'px)'
+    @$('.wizard-container').css('transform', translate_string)
+    @$('.wizard-container').css('-webkit-transform', translate_string)
+
+  legacy_go_to: (view_id) ->
+    # For older browsers - switch wizard views by changing the screen.
+    @$('.wizard-view').css('display', 'none')
+    @$('#' + view_id).css('display', 'block')
\ No newline at end of file
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index a7f2eafd1c..6cd5040072 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -38,98 +38,100 @@
 
   <!-- Tells coffeescript whether there are hints to show. -->
   <span id="hints-exist" style="display:none">${hints_exist}</span>
-
-  <div class="wizard-view" id="p1">
-    <p>
-    <em> Optional. </em> Help us improve our hints!  Which hint was most helpful to you?
-    </p>
-
-    <div id="pk-list" data-pk-list='${json_pk_list}' style="display:none"> </div>
-
-    % for answer, pk_dict in answer_to_hints.items():
-        % for hint_pk, hint_text in pk_dict.items():
-            <p>
-            <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
-            ${hint_text}
-            </p>
-        % endfor
-    % endfor
-
-    <p>
-    Don't like any of the hints above? 
-    <a class="wizard-link" dest="p2" href="javascript: void(0);">
-      Write your own!
-    </a></p>
-  </div>
-
-  <div class="wizard-view" id="p2">
-    % if hints_exist:
+  <div class="wizard-viewbox"><div class="wizard-container">
+    <div class="wizard-view" id="p1">
       <p>
-      Choose the incorrect answer for which you want to write a hint:
-      </p>
-    % else:
-    <p>
-      <em>Optional.</em>  Help other students by submitting a hint!  Pick one of your previous
-      answers for which you would like to write a hint:
-    </p>
-    % endif
-    % for answer in user_submissions:
-        <a class="answer-choice" href="javascript: void(0)" value="${answer}">${answer}</a><br />
-    % endfor
-    % if hints_exist:
-      <br />
-      <a href="javascript: void(0);" class="wizard-link" dest="p1"> Back </a>
-    % endif
-
-  </div>
-
-  <div class="wizard-view" id="p3">
-
-    <p>
-      Write a hint for other students who get the wrong answer of <span id="blank-answer"></span>.
-    </p>
-    <p>Read about <a class="expand" data-target="goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
-    <div id="goodhint" style="display:none">
-      <h4>What makes a good hint?</h4>
-
-      <p>It depends on the type of problem you ran into. For stupid errors --
-      an arithmetic error or similar -- simply letting the student you'll be
-      helping to check their signs is sufficient.</p>
-
-      <p>For deeper errors of understanding, the best hints allow students to
-      discover a contradiction in how they are thinking about the
-      problem. An example that clearly demonstrates inconsistency or
-      <a href="http://en.wikipedia.org/wiki/Cognitive_dissonance" target="_blank"> cognitive dissonace </a>
-      is ideal, although in most cases, not possible.</p>
-
-      <p>
-        Good hints either:
-        <ul>
-          <li> Point out the specific misunderstanding your classmate might have </li>
-          <li> Point to concepts or theories where your classmates might have a
-          misunderstanding </li>
-          <li> Show simpler, analogous examples. </li>
-          <li> Provide references to relevant parts of the text </li>
-        </ul>
+      <em> Optional. </em> Help us improve our hints!  Which hint was most helpful to you?
       </p>
 
-      <p>Still, remember even a crude hint -- virtually anything short of
-      giving away the answer -- is better than no hint.</p>
+      <div id="pk-list" data-pk-list='${json_pk_list}' style="display:none"> </div>
+
+      % for answer, pk_dict in answer_to_hints.items():
+          % for hint_pk, hint_text in pk_dict.items():
+              <p>
+              <input class="vote" data-answer="${answer}" data-hintno="${hint_pk}" type="button" value="Vote">
+              ${hint_text}
+              </p>
+          % endfor
+      % endfor
 
       <p>
-        <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
-      </p>
+      Don't like any of the hints above? 
+      <a class="wizard-link" dest="p2" href="javascript: void(0);">
+        Write your own!
+      </a></p>
     </div>
 
-    <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
-Write your hint here.  Please don't give away the correct answer.
-    </textarea>
-    <br /><br />
-    <input class="submit-hint" data-answer="${answer}" type="button" value="Submit">
-    <br /><br />
-    <a href="javascript: void(0);" class="wizard-link" dest="p2"> Back </a>
-  </div>
+    <div class="wizard-view" id="p2">
+      % if hints_exist:
+        <p>
+        Choose the incorrect answer for which you want to write a hint:
+        </p>
+      % else:
+      <p>
+        <em>Optional.</em>  Help other students by submitting a hint!  Pick one of your previous
+        answers for which you would like to write a hint:
+      </p>
+      % endif
+      % for answer in user_submissions:
+          <a class="answer-choice" href="javascript: void(0)" value="${answer}">${answer}</a><br />
+      % endfor
+      % if hints_exist:
+        <!-- A placeholder for the Back button, which is relatively-positioned -->
+        <p> &nbsp </p>
+        <a href="javascript: void(0);" class="wizard-link bottom" dest="p1"> Back </a>
+      % endif
 
+    </div>
+
+    <div class="wizard-view" id="p3">
+
+      <p>
+        Write a hint for other students who get the wrong answer of <span id="blank-answer"></span>.
+      </p>
+      <p>Read about <a class="expand" data-target="goodhint" href="javascript:void(0);">what makes a good hint</a>.</p>
+
+      <textarea cols="50" class="custom-hint" data-answer="${answer}" style="height: 200px">
+Write your hint here.  Please don't give away the correct answer.
+      </textarea>
+      <br /><br />
+      <input class="submit-hint" data-answer="${answer}" type="button" value="Submit">
+      <div id="goodhint" style="display:none">
+        <h4>What makes a good hint?</h4>
+
+        <p>It depends on the type of problem you ran into. For stupid errors --
+        an arithmetic error or similar -- simply letting the student you'll be
+        helping to check their signs is sufficient.</p>
+
+        <p>For deeper errors of understanding, the best hints allow students to
+        discover a contradiction in how they are thinking about the
+        problem. An example that clearly demonstrates inconsistency or
+        <a href="http://en.wikipedia.org/wiki/Cognitive_dissonance" target="_blank"> cognitive dissonace </a>
+        is ideal, although in most cases, not possible.</p>
+
+        <p>
+          Good hints either:
+          <ul>
+            <li> Point out the specific misunderstanding your classmate might have </li>
+            <li> Point to concepts or theories where your classmates might have a
+            misunderstanding </li>
+            <li> Show simpler, analogous examples. </li>
+            <li> Provide references to relevant parts of the text </li>
+          </ul>
+        </p>
+
+        <p>Still, remember even a crude hint -- virtually anything short of
+        giving away the answer -- is better than no hint.</p>
+
+        <p>
+          <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
+        </p>
+      </div>
+      <br />
+      <a href="javascript: void(0);" class="wizard-link" dest="p2"> Back </a>
+    </div>
+  <!-- Close wizard contaner and wizard viewbox. -->
+  </div></div>
 
 
 </%def>

From 42202520551cfb9988723599565cc8a37b9fe961 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 2 Aug 2013 09:22:22 -0400
Subject: [PATCH 21/28] Fixed terribly annoying issues with back button.  Back
 button is now on the bottom of the hint div, no matter what.

---
 .../xmodule/css/crowdsource_hinter/display.scss   |  5 -----
 .../js/src/crowdsource_hinter/display.coffee      | 15 +++++++++++++--
 common/templates/hinter_display.html              | 11 ++++++-----
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
index ce40d10b53..0c479ab5cb 100644
--- a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
+++ b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
@@ -37,8 +37,3 @@
   overflow: hidden;
   position: relative;
 }
-
-.bottom {
-  position: absolute;
-  bottom: 0;
-}
\ No newline at end of file
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 3ecf73a0dc..2e99b107f9 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -48,7 +48,7 @@ class @Hinter
     else
       @$(target).css('display', 'none')
     # Fix positioning errors with the bottom class.
-    @$('.bottom').removeClass('bottom').addClass('bottom')
+    @set_bottom_links()
 
   vote: (eventObj) =>
     # Make an ajax request with the user's vote.
@@ -87,6 +87,15 @@ class @Hinter
     @$('#blank-answer').html(@answer)
     @go_to('p3')
 
+  set_bottom_links: =>
+    # Makes each .bottom class stick to the bottom of .wizard-viewbox
+    @$('.bottom').css('margin-top', '0px')
+    viewbox_height = parseInt(@$('.wizard-viewbox').css('height'), 10)
+    @$('.bottom').each((index, obj) ->
+      view_height = parseInt($(obj).parent().css('height'), 10)
+      $(obj).css('margin-top', (viewbox_height - view_height) + 'px')
+    )
+
   render: (content) =>
     if content
       # Trim leading and trailing whitespace
@@ -127,8 +136,10 @@ class @Hinter
     translate_string = 'translateX(' +id_to_index[view_id] * -1 * parseInt($('#' + view_id).css('width'), 10) + 'px)'
     @$('.wizard-container').css('transform', translate_string)
     @$('.wizard-container').css('-webkit-transform', translate_string)
+    @set_bottom_links()
 
   legacy_go_to: (view_id) ->
     # For older browsers - switch wizard views by changing the screen.
     @$('.wizard-view').css('display', 'none')
-    @$('#' + view_id).css('display', 'block')
\ No newline at end of file
+    @$('#' + view_id).css('display', 'block')
+    @set_bottom_links()
\ No newline at end of file
diff --git a/common/templates/hinter_display.html b/common/templates/hinter_display.html
index 6cd5040072..12f6b9f2f4 100644
--- a/common/templates/hinter_display.html
+++ b/common/templates/hinter_display.html
@@ -77,9 +77,9 @@
           <a class="answer-choice" href="javascript: void(0)" value="${answer}">${answer}</a><br />
       % endfor
       % if hints_exist:
-        <!-- A placeholder for the Back button, which is relatively-positioned -->
-        <p> &nbsp </p>
-        <a href="javascript: void(0);" class="wizard-link bottom" dest="p1"> Back </a>
+        <p class="bottom">
+          <a href="javascript: void(0);" class="wizard-link" dest="p1"> Back </a>
+        </p>
       % endif
 
     </div>
@@ -127,8 +127,9 @@ Write your hint here.  Please don't give away the correct answer.
           <a href="http://www.apa.org/education/k12/misconceptions.aspx?item=2" target="_blank">Learn even more</a>
         </p>
       </div>
-      <br />
-      <a href="javascript: void(0);" class="wizard-link" dest="p2"> Back </a>
+      <p class="bottom">
+        <a href="javascript: void(0);" class="wizard-link" dest="p2"> Back </a>
+      </p>
     </div>
   <!-- Close wizard contaner and wizard viewbox. -->
   </div></div>

From 69fbe77dcb82840cc8fea78fac1b103fe69858cd Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Thu, 15 Aug 2013 10:57:06 -0400
Subject: [PATCH 22/28] Fixed a rebase error in responsetypes.

Fixed a css bug in the hinter.
---
 common/lib/capa/capa/responsetypes.py                        | 2 +-
 .../lib/xmodule/xmodule/css/crowdsource_hinter/display.scss  | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 182266c21a..192d6c0663 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -1812,7 +1812,7 @@ class FormulaResponse(LoncapaResponse):
                     var_dict,
                     dict(),
                     answer,
-                    cs=self.case_sensitive,
+                    case_sensitive=self.case_sensitive,
                 ))
             except UndefinedVariable as uv:
                 log.debug(
diff --git a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
index 0c479ab5cb..dab94ed2f7 100644
--- a/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
+++ b/common/lib/xmodule/xmodule/css/crowdsource_hinter/display.scss
@@ -20,7 +20,8 @@
 
 .wizard-view {
   float: left;
-  width: 800px;
+  width: 790px;
+  margin-right: 10px;
 }
 
 .wizard-container {
@@ -33,7 +34,7 @@
 }
 
 .wizard-viewbox {
-  width: 790px;
+  width: 800px;
   overflow: hidden;
   position: relative;
 }

From e6067d88145992e9b6ebc02ff78bf34e088081b7 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Mon, 19 Aug 2013 13:58:59 -0400
Subject: [PATCH 23/28] Addressed PR comments.

Fixed coffeescript event logging error.

Fixed crowdsourced hinter dependence on self.field.append() not working.
---
 common/lib/capa/capa/responsetypes.py         |  4 +-
 .../lib/xmodule/xmodule/crowdsource_hinter.py | 48 ++++++++++---------
 .../xmodule/js/src/capa/display.coffee        |  1 +
 3 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 192d6c0663..550042d1df 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -923,8 +923,8 @@ class NumericalResponse(LoncapaResponse):
         with this problem's tolerance.
         """
         return compare_with_tolerance(
-            evaluator(dict(), dict(), a),
-            evaluator(dict(), dict(), b),
+            evaluator({}, {}, a),
+            evaluator({}, {}, b),
             self.tolerance
         )
 
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 74b5f7b36e..90699beda6 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -7,6 +7,7 @@ Currently experimental - not for instructor use, yet.
 import logging
 import json
 import random
+import copy
 
 from pkg_resources import resource_string
 
@@ -82,17 +83,17 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
             log.exception('Unable to find a capa problem child.')
             return
 
-        self.is_formula = (type(responder) == FormulaResponse)
+        self.is_formula = isinstance(self, FormulaResponse)
         if self.is_formula:
             self.answer_to_str = self.formula_answer_to_str
         else:
             self.answer_to_str = self.numerical_answer_to_str
         # compare_answer is expected to return whether its two inputs are close enough
         # to be equal, or raise a StudentInputError if one of the inputs is malformatted.
-        try:
+        if hasattr(responder, 'compare_answer') and hasattr(responder, 'validate_answer'):
             self.compare_answer = responder.compare_answer
             self.validate_answer = responder.validate_answer
-        except AttributeError:
+        else:
             # This response type is not supported!
             log.exception('Response type not supported for hinting: ' + str(responder))
 
@@ -199,43 +200,43 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         if answer not in self.user_submissions:
             self.user_submissions += [answer]
 
-        # Next, find all of the hints that could possibly go with this answer.
-        # Make a local copy of self.hints - this means we only need to do one json unpacking.
-        # (This is because xblocks storage makes the following command a deep copy.)
-        local_hints = self.hints
         # For all answers similar enough to our own, accumulate all hints together.
         # Also track the original answer of each hint.
         matching_answers = self.get_matching_answers(answer)
         matching_hints = {}
         for matching_answer in matching_answers:
-            temp_dict = local_hints[matching_answer]
+            temp_dict = copy.deepcopy(self.hints[matching_answer])
             for key, value in temp_dict.items():
                 # Each value now has hint, votes, matching_answer.
                 temp_dict[key] = value + [matching_answer]
-            matching_hints.update(local_hints[matching_answer])
+            matching_hints.update(temp_dict)
         # matching_hints now maps pk's to lists of [hint, votes, matching_answer]
 
         # Finally, randomly choose a subset of matching_hints to actually show.
-        if len(matching_hints) == 0:
+        if not matching_hints:
             # No hints to give.  Return.
             return
         # Get the top hint, plus two random hints.
         n_hints = len(matching_hints)
         hints = []
-        best_hint_index = max(matching_hints, key=lambda key: matching_hints[key][1])
+        # max(dict) returns the maximum key in dict.
+        # The key function takes each pk, and returns the number of votes for the
+        # hint with that pk.
+        best_hint_index = max(matching_hints, key=lambda pk: matching_hints[pk][1])
         hints.append(matching_hints[best_hint_index][0])
         best_hint_answer = matching_hints[best_hint_index][2]
         # The brackets surrounding the index are for backwards compatability purposes.
         # (It used to be that each answer was paired with multiple hints in a list.)
         self.previous_answers += [[best_hint_answer, [best_hint_index]]]
-        for i in xrange(min(2, n_hints-1)):
+        for i in xrange(min(2, n_hints - 1)):
             # Keep making random hints until we hit a target, or run out.
-            go_on = False
-            while not go_on:
+            while True:
+                # random.choice randomly chooses an element from its input list.
+                # (We then unpack the item, in this case data for a hint.)
                 (hint_index, (rand_hint, votes, hint_answer)) =\
                     random.choice(matching_hints.items())
-                if not rand_hint in hints:
-                    go_on = True
+                if rand_hint not in hints:
+                    break
             hints.append(rand_hint)
             self.previous_answers += [[hint_answer, [hint_index]]]
         return {'hints': hints,
@@ -297,7 +298,7 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         ans = data['answer']
         if not self.validate_answer(ans):
             # Uh oh.  Invalid answer.
-            log.exception('Failure in hinter tally_vote: Unable to parse answer: ' + ans)
+            log.exception('Failure in hinter tally_vote: Unable to parse answer: {ans}'.format(ans=ans))
             return {'error': 'Failure in voting!'}
         hint_pk = str(data['hint'])
         # We use temp_dict because we need to do a direct write for the database to update.
@@ -305,8 +306,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         try:
             temp_dict[ans][hint_pk][1] += 1
         except KeyError:
-            log.exception('Failure in hinter tally_vote: User voted for non-existant hint: Answer=' +
-                          ans + ' pk=' + hint_pk)
+            log.exception('''Failure in hinter tally_vote: User voted for non-existant hint:
+                             Answer={ans} pk={hint_pk}'''.format(ans=ans, hint_pk=hint_pk))
             return {'error': 'Failure in voting!'}
         self.hints = temp_dict
         # Don't let the user vote again!
@@ -317,13 +318,13 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         hint_and_votes = []
         for answer, vote_pk in pk_list:
             if not self.validate_answer(answer):
-                log.exception('In hinter tally_vote, couldn\'t parse ' + answer)
+                log.exception('In hinter tally_vote, couldn\'t parse {ans}'.format(ans=answer))
                 continue
             try:
                 hint_and_votes.append(temp_dict[answer][str(vote_pk)])
             except KeyError:
-                log.exception('In hinter tally_vote, couldn\'t find: '
-                              + answer + ', ' + str(vote_pk))
+                log.exception('In hinter tally_vote, couldn\'t find: {ans}, {vote_pk}'.format(
+                              ans=answer, vote_pk=str(vote_pk)))
 
         hint_and_votes.sort(key=lambda pair: pair[1], reverse=True)
         # Reset self.previous_answers and user_submissions.
@@ -345,7 +346,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         hint = escape(data['hint'])
         answer = data['answer']
         if not self.validate_answer(answer):
-            log.exception('Failure in hinter submit_hint: Unable to parse answer: ' + answer)
+            log.exception('Failure in hinter submit_hint: Unable to parse answer: {ans}'.format(
+                          ans=answer))
             return {'error': 'Could not submit answer'}
         # Only allow a student to vote or submit a hint once.
         if self.user_voted:
diff --git a/common/lib/xmodule/xmodule/js/src/capa/display.coffee b/common/lib/xmodule/xmodule/js/src/capa/display.coffee
index 7263dde1f0..ab64617644 100644
--- a/common/lib/xmodule/xmodule/js/src/capa/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/capa/display.coffee
@@ -247,6 +247,7 @@ class @Problem
             @updateProgress response
           else
             @gentle_alert response.success
+        Logger.log 'problem_graded', [@answers, response.contents], @url
 
     if not abort_submission
       $.ajaxWithPrefix("#{@url}/problem_check", settings)

From 68bb45ab67dc3dee4215e2c166ff898544099cd9 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Tue, 20 Aug 2013 14:44:12 -0400
Subject: [PATCH 24/28] Added jasmine tests to crowdsource_hinter.  UI is not
 covered; only event-inteception is covered.

---
 .../js/fixtures/crowdsource_hinter.html       | 52 ++++++++++++++++++
 .../xmodule/js/spec/capa/display_spec.coffee  | 12 ++++-
 .../crowdsource_hinter/display_spec.coffee    | 54 +++++++++++++++++++
 .../xmodule/js/src/capa/display.coffee        |  1 -
 .../js/src/crowdsource_hinter/display.coffee  |  2 +-
 5 files changed, 118 insertions(+), 3 deletions(-)
 create mode 100644 common/lib/xmodule/xmodule/js/fixtures/crowdsource_hinter.html
 create mode 100644 common/lib/xmodule/xmodule/js/spec/crowdsource_hinter/display_spec.coffee

diff --git a/common/lib/xmodule/xmodule/js/fixtures/crowdsource_hinter.html b/common/lib/xmodule/xmodule/js/fixtures/crowdsource_hinter.html
new file mode 100644
index 0000000000..02122017bd
--- /dev/null
+++ b/common/lib/xmodule/xmodule/js/fixtures/crowdsource_hinter.html
@@ -0,0 +1,52 @@
+<li id="vert-0" data-id="i4x://Me/19.002/crowdsource_hinter/crowdsource_hinter_def7a1142dd0">
+    
+
+<section class="xmodule_display xmodule_CrowdsourceHinterModule" data-type="Hinter" id="hinter-root">
+    
+
+<section class="xmodule_display xmodule_CapaModule" data-type="Problem" id="problem">
+  <section id="problem_i4x-Me-19_002-problem-Numerical_Input" class="problems-wrapper" data-problem-id="i4x://Me/19.002/problem/Numerical_Input" data-url="/courses/Me/19.002/Test/modx/i4x://Me/19.002/problem/Numerical_Input" data-progress_status="done" data-progress_detail="1/1">
+
+
+    <h2 class="problem-header">
+      Numerical Input
+    </h2>
+
+    <section class="problem-progress">(1/1 points)</section>
+
+    <section class="problem">
+      <div><p>The answer is 2*x^2*y + 5
+          </p><span><br><span> Answer =</span>
+          <section id="inputtype_i4x-Me-19_002-problem-Numerical_Input_2_1" class="text-input-dynamath capa_inputtype ">
+            <div class="correct " id="status_i4x-Me-19_002-problem-Numerical_Input_2_1">
+              <input type="text" name="input_i4x-Me-19_002-problem-Numerical_Input_2_1" id="input_i4x-Me-19_002-problem-Numerical_Input_2_1" aria-describedby="answer_i4x-Me-19_002-problem-Numerical_Input_2_1" value="2*x^2*y +5" class="math" size="40">
+
+        </div></section></span>
+
+        <input type="file" />
+
+        <section class="solution-span"><span id="solution_i4x-Me-19_002-problem-Numerical_Input_solution_1"></span></section></div>
+
+      <section class="action">
+        <input type="hidden" name="problem_id" value="Numerical Input">
+
+        <input class="check Check" type="button" value="Check">
+        <button class="show"><span class="show-label">Show Answer(s)</span> <span class="sr">(for question(s) above - adjacent to each field)</span></button>
+      </section>
+    </section>
+  </section>
+
+</section>
+
+
+
+<div id="i4x_Me_19_002_problem_Numerical_Input_setup"></div>
+
+
+
+<section class="crowdsource-wrapper" data-url="/courses/Me/19.002/Test/modx/i4x://Me/19.002/crowdsource_hinter/crowdsource_hinter_def7a1142dd0" data-child-url="/courses/Me/19.002/Test/modx/i4x://Me/19.002/problem/Numerical_Input" style="display: none;"> </section>
+</section>
+
+
+
+</li>
\ No newline at end of file
diff --git a/common/lib/xmodule/xmodule/js/spec/capa/display_spec.coffee b/common/lib/xmodule/xmodule/js/spec/capa/display_spec.coffee
index 33d74e2335..111174a0b4 100644
--- a/common/lib/xmodule/xmodule/js/spec/capa/display_spec.coffee
+++ b/common/lib/xmodule/xmodule/js/spec/capa/display_spec.coffee
@@ -125,9 +125,10 @@ describe 'Problem', ->
         expect(@problem.bind).toHaveBeenCalled()
 
   describe 'check_fd', ->
-    xit 'should have specs written for this functionality', ->
+    xit 'should have more specs written for this functionality', ->
       expect(false)
 
+
   describe 'check', ->
     beforeEach ->
       @problem = new Problem($('.xmodule_display'))
@@ -137,6 +138,15 @@ describe 'Problem', ->
       @problem.check()
       expect(Logger.log).toHaveBeenCalledWith 'problem_check', 'foo=1&bar=2'
 
+    it 'log the problem_graded event, after the problem is done grading.', ->
+      spyOn($, 'postWithPrefix').andCallFake (url, answers, callback) ->
+        response = 
+          success: 'correct'
+          contents: 'mock grader response'
+        callback(response)
+      @problem.check()
+      expect(Logger.log).toHaveBeenCalledWith 'problem_graded', ['foo=1&bar=2', 'mock grader response'], @problem.url
+
     it 'submit the answer for check', ->
       spyOn $, 'postWithPrefix'
       @problem.check()
diff --git a/common/lib/xmodule/xmodule/js/spec/crowdsource_hinter/display_spec.coffee b/common/lib/xmodule/xmodule/js/spec/crowdsource_hinter/display_spec.coffee
new file mode 100644
index 0000000000..917741f8af
--- /dev/null
+++ b/common/lib/xmodule/xmodule/js/spec/crowdsource_hinter/display_spec.coffee
@@ -0,0 +1,54 @@
+describe 'Crowdsourced hinter', ->  
+  beforeEach ->
+    window.update_schematics = ->
+    jasmine.stubRequests()
+    # note that the fixturesPath is set in spec/helper.coffee
+    loadFixtures 'crowdsource_hinter.html'
+    @hinter = new Hinter($('#hinter-root'))
+
+  describe 'high-level integration tests', ->
+    # High-level, happy-path tests for integration with capa problems.
+    beforeEach ->
+      # Make a more thorough $.postWithPrefix mock.
+      spyOn($, 'postWithPrefix').andCallFake( ->
+        last_argument = arguments[arguments.length - 1]
+        if typeof last_argument == 'function'
+          response = 
+            success: 'incorrect'
+            contents: 'mock grader response'
+          last_argument(response)
+      )
+      @problem = new Problem($('#problem'))
+      @problem.bind()
+
+    it 'knows when a capa problem is graded, using check.', ->
+      @problem.answers = 'test answer'
+      @problem.check()
+      expect($.postWithPrefix).toHaveBeenCalledWith("#{@hinter.url}/get_hint", 'test answer', jasmine.any(Function))
+
+    it 'knows when a capa problem is graded usig check_fd.', ->
+      spyOn($, 'ajaxWithPrefix').andCallFake((url, settings) ->
+        response = 
+          success: 'incorrect'
+          contents: 'mock grader response'
+        settings.success(response)
+      )
+      @problem.answers = 'test answer'
+      @problem.check_fd()
+      expect($.postWithPrefix).toHaveBeenCalledWith("#{@hinter.url}/get_hint", 'test answer', jasmine.any(Function))
+
+  describe 'capture_problem', ->
+    beforeEach ->
+      spyOn($, 'postWithPrefix').andReturn(null)
+
+    it 'gets hints for an incorrect answer', ->
+      data = ['some answers', '<thing class="incorrect">']
+      @hinter.capture_problem('problem_graded', data, 'fake element')
+      expect($.postWithPrefix).toHaveBeenCalledWith("#{@hinter.url}/get_hint", 'some answers', jasmine.any(Function))
+
+    it 'gets feedback for a correct answer', ->
+      data = ['some answers', '<thing class="correct">']
+      @hinter.capture_problem('problem_graded', data, 'fake element')
+      expect($.postWithPrefix).toHaveBeenCalledWith("#{@hinter.url}/get_feedback", 'some answers', jasmine.any(Function))
+
+
diff --git a/common/lib/xmodule/xmodule/js/src/capa/display.coffee b/common/lib/xmodule/xmodule/js/src/capa/display.coffee
index ab64617644..61df101d08 100644
--- a/common/lib/xmodule/xmodule/js/src/capa/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/capa/display.coffee
@@ -19,7 +19,6 @@ class @Problem
 
     problem_prefix = @element_id.replace(/problem_/,'')
     @inputs = @$("[id^=input_#{problem_prefix}_]")
-
     @$('section.action input:button').click @refreshAnswers
     @$('section.action input.check').click @check_fd
     @$('section.action input.reset').click @reset
diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index 2e99b107f9..c53a2e2066 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -96,7 +96,7 @@ class @Hinter
       $(obj).css('margin-top', (viewbox_height - view_height) + 'px')
     )
 
-  render: (content) =>
+  render: (content) ->
     if content
       # Trim leading and trailing whitespace
       content = content.replace /^\s+|\s+$/g, ""

From 1f9eafeedecb164b87963c3ee2b6592220e64d18 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Wed, 21 Aug 2013 15:10:34 -0400
Subject: [PATCH 25/28] Addressed some minor PR comments.

---
 .../xmodule/js/src/crowdsource_hinter/display.coffee        | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
index c53a2e2066..f9f3e43826 100644
--- a/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/crowdsource_hinter/display.coffee
@@ -28,10 +28,6 @@ class @Hinter
   $: (selector) ->
     $(selector, @el)
 
-  jq_escape: (string) =>
-    # Escape a string for jquery selector use.
-    return string.replace(/[!"#$%&'()*+,.\/:;<=>?@\[\\\]^`{|}~]/g, '\\$&')
-
   bind: =>
     @$('input.vote').click @vote
     @$('input.submit-hint').click @submit_hint
@@ -99,7 +95,7 @@ class @Hinter
   render: (content) ->
     if content
       # Trim leading and trailing whitespace
-      content = content.replace /^\s+|\s+$/g, ""
+      content = content.trim()
 
     if content
       @el.html(content)

From 74ed2dafb3e07ed085e920eb4eba2d3024846b22 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Fri, 23 Aug 2013 10:19:36 -0400
Subject: [PATCH 26/28] Improved docstrings.

---
 .../lib/xmodule/xmodule/crowdsource_hinter.py |  7 +++++--
 lms/djangoapps/instructor/hint_manager.py     | 19 ++++++++++++++++---
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index 90699beda6..f2d21c459b 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -182,9 +182,10 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         Args:
         `data` -- must be interpretable by answer_to_str.
         Output keys:
-            - 'best_hint' is the hint text with the most votes.
-            - 'rand_hint_1' and 'rand_hint_2' are two random hints to the answer in `data`.
+            - 'hints' is a list of hint strings to show to the user.
             - 'answer' is the parsed answer that was submitted.
+        Will record the user's wrong answer in user_submissions, and the hints shown
+        in previous_answers.
         """
         # First, validate our inputs.
         try:
@@ -251,6 +252,8 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         Output keys:
             - 'answer_to_hints': a nested dictionary.
               answer_to_hints[answer][hint_pk] returns the text of the hint.
+            - 'user_submissions': the same thing as self.user_submissions.  A list of
+              the answers that the user previously submitted.
         """
         # The student got it right.
         # Did he submit at least one wrong answer?
diff --git a/lms/djangoapps/instructor/hint_manager.py b/lms/djangoapps/instructor/hint_manager.py
index 3616445543..71c2beb7d5 100644
--- a/lms/djangoapps/instructor/hint_manager.py
+++ b/lms/djangoapps/instructor/hint_manager.py
@@ -1,8 +1,10 @@
 """
 Views for hint management.
 
-Along with the crowdsource_hinter xmodule, this code is still
-experimental, and should not be used in new courses, yet.
+Get to these views through courseurl/hint_manager.
+For example: https://courses.edx.org/courses/MITx/2.01x/2013_Spring/hint_manager
+
+These views will only be visible if MITX_FEATURES['ENABLE_HINTER_INSTRUCTOR_VIEW'] = True
 """
 
 import json
@@ -23,6 +25,9 @@ from xmodule.modulestore.django import modulestore
 
 @ensure_csrf_cookie
 def hint_manager(request, course_id):
+    """
+    The URL landing function for all calls to the hint manager, both POST and GET.
+    """
     try:
         get_course_with_access(request.user, course_id, 'staff', depth=None)
     except Http404:
@@ -172,7 +177,13 @@ def change_votes(request, course_id, field):
     Updates the number of votes.
 
     The numbered fields of `request.POST` contain [problem_id, answer, pk, new_votes] tuples.
-    - Very similar to `delete_hints`.  Is there a way to merge them?  Nah, too complicated.
+    See `delete_hints`.
+
+    Example `request.POST`:
+    {'op': 'delete_hints',
+     'field': 'mod_queue',
+      1: ['problem_whatever', '42.0', '3', 42],
+      2: ['problem_whatever', '32.5', '12', 9001]}
     """
 
     for key in request.POST:
@@ -233,6 +244,8 @@ def approve(request, course_id, field):
     hint list.  POST:
     op, field
     (some number) -> [problem, answer, pk]
+
+    The numbered fields are analogous to those in `delete_hints` and `change_votes`.
     """
 
     for key in request.POST:

From 6e64e994f66138533b844c4def9755140b95ef74 Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Mon, 26 Aug 2013 09:46:29 -0400
Subject: [PATCH 27/28] Fixed a test broken when the mixed modulestore was
 introduced.

---
 lms/djangoapps/instructor/hint_manager.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lms/djangoapps/instructor/hint_manager.py b/lms/djangoapps/instructor/hint_manager.py
index 71c2beb7d5..f97115f19b 100644
--- a/lms/djangoapps/instructor/hint_manager.py
+++ b/lms/djangoapps/instructor/hint_manager.py
@@ -215,7 +215,7 @@ def add_hint(request, course_id, field):
     # Validate the answer.  This requires initializing the xmodules, which
     # is annoying.
     loc = Location(problem_id)
-    descriptors = modulestore().get_items(loc)
+    descriptors = modulestore().get_items(loc, course_id=course_id)
     m_d_c = model_data.ModelDataCache(descriptors, course_id, request.user)
     hinter_module = module_render.get_module(request.user, request, loc, m_d_c, course_id)
     if not hinter_module.validate_answer(answer):

From 444f51d6de684d7f40c388d16e02b00a69e5391c Mon Sep 17 00:00:00 2001
From: Felix Sun <fephsun@gmail.com>
Date: Tue, 27 Aug 2013 09:41:29 -0400
Subject: [PATCH 28/28] Fixed some pep/pylint violations.

---
 common/lib/capa/capa/responsetypes.py                | 12 +++++-------
 common/lib/xmodule/xmodule/crowdsource_hinter.py     |  4 ++--
 .../xmodule/xmodule/tests/test_crowdsource_hinter.py |  8 +++++---
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index 550042d1df..b53f38fd90 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -915,16 +915,14 @@ class NumericalResponse(LoncapaResponse):
         else:
             return CorrectMap(self.answer_id, 'incorrect')
 
-    # TODO: add check_hint_condition(self, hxml_set, student_answers)
-
-    def compare_answer(self, a, b):
+    def compare_answer(self, ans1, ans2):
         """
         Outside-facing function that lets us compare two numerical answers,
         with this problem's tolerance.
         """
         return compare_with_tolerance(
-            evaluator({}, {}, a),
-            evaluator({}, {}, b),
+            evaluator({}, {}, ans1),
+            evaluator({}, {}, ans2),
             self.tolerance
         )
 
@@ -1886,11 +1884,11 @@ class FormulaResponse(LoncapaResponse):
         else:
             return "incorrect"
 
-    def compare_answer(self, a, b):
+    def compare_answer(self, ans1, ans2):
         """
         An external interface for comparing whether a and b are equal.
         """
-        internal_result = self.check_formula(a, b, self.samples)
+        internal_result = self.check_formula(ans1, ans2, self.samples)
         return internal_result == "correct"
 
     def validate_answer(self, answer):
diff --git a/common/lib/xmodule/xmodule/crowdsource_hinter.py b/common/lib/xmodule/xmodule/crowdsource_hinter.py
index f2d21c459b..7e538efa24 100644
--- a/common/lib/xmodule/xmodule/crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/crowdsource_hinter.py
@@ -229,12 +229,12 @@ class CrowdsourceHinterModule(CrowdsourceHinterFields, XModule):
         # The brackets surrounding the index are for backwards compatability purposes.
         # (It used to be that each answer was paired with multiple hints in a list.)
         self.previous_answers += [[best_hint_answer, [best_hint_index]]]
-        for i in xrange(min(2, n_hints - 1)):
+        for _ in xrange(min(2, n_hints - 1)):
             # Keep making random hints until we hit a target, or run out.
             while True:
                 # random.choice randomly chooses an element from its input list.
                 # (We then unpack the item, in this case data for a hint.)
-                (hint_index, (rand_hint, votes, hint_answer)) =\
+                (hint_index, (rand_hint, _, hint_answer)) =\
                     random.choice(matching_hints.items())
                 if rand_hint not in hints:
                     break
diff --git a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
index d28d2ee06b..8347b71076 100644
--- a/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
+++ b/common/lib/xmodule/xmodule/tests/test_crowdsource_hinter.py
@@ -120,9 +120,9 @@ class CHModuleFactory(object):
                 return False
         responder.validate_answer = validate_answer
 
-        def compare_answer(a, b):
+        def compare_answer(ans1, ans2):
             """ A fake answer comparer """
-            return a == b
+            return ans1 == ans2
         responder.compare_answer = compare_answer
 
         capa_module.lcp.responders = {'responder0': responder}
@@ -189,11 +189,13 @@ class VerticalWithModulesFactory(object):
 
     @staticmethod
     def next_num():
+        """Increments a global counter for naming."""
         CHModuleFactory.num += 1
         return CHModuleFactory.num
 
     @staticmethod
     def create():
+        """Make a vertical."""
         model_data = {'data': VerticalWithModulesFactory.sample_problem_xml}
         system = get_test_system()
         descriptor = VerticalDescriptor.from_xml(VerticalWithModulesFactory.sample_problem_xml, system)
@@ -532,7 +534,7 @@ class CrowdsourceHinterTest(unittest.TestCase):
         """
         mock_module = CHModuleFactory.create()
 
-        def fake_get_hint(get):
+        def fake_get_hint(_):
             """
             Creates a rendering dictionary, with which we can test
             the templates.