From ea0027f3386b0910d2fa079bde4777b7314abcd5 Mon Sep 17 00:00:00 2001
From: "J. Cliff Dyer" <cdyer@edx.org>
Date: Tue, 18 Apr 2017 16:47:11 -0400
Subject: [PATCH] refactor CAPA to use scorable xblock mixin for TNL-6594

---
 common/lib/capa/capa/capa_problem.py          |  36 ++-
 common/lib/xmodule/xmodule/capa_base.py       | 249 ++++++++++--------
 common/lib/xmodule/xmodule/capa_module.py     |   3 +-
 .../xmodule/xmodule/tests/test_capa_module.py |  59 +++--
 .../tests/test_delay_between_attempts.py      |   5 +-
 lms/djangoapps/grades/signals/handlers.py     |  38 ++-
 .../grades/tests/integration/test_events.py   |  12 +-
 lms/djangoapps/instructor_task/api_helper.py  |  19 +-
 .../tasks_helper/module_state.py              |  81 ++----
 .../instructor_task/tests/test_integration.py |   5 +-
 .../instructor_task/tests/test_tasks.py       |  73 +----
 11 files changed, 272 insertions(+), 308 deletions(-)

diff --git a/common/lib/capa/capa/capa_problem.py b/common/lib/capa/capa/capa_problem.py
index c5993e0a84..1f44f79260 100644
--- a/common/lib/capa/capa/capa_problem.py
+++ b/common/lib/capa/capa/capa_problem.py
@@ -304,26 +304,25 @@ class LoncapaProblem(object):
             maxscore += responder.get_max_score()
         return maxscore
 
-    def get_score(self):
+    def calculate_score(self, correct_map=None):
         """
         Compute score for this problem.  The score is the number of points awarded.
         Returns a dictionary {'score': integer, from 0 to get_max_score(),
                               'total': get_max_score()}.
+
+        Takes an optional correctness map for use in the rescore workflow.
         """
+        if correct_map is None:
+            correct_map = self.correct_map
         correct = 0
-        for key in self.correct_map:
+        for key in correct_map:
             try:
-                correct += self.correct_map.get_npoints(key)
+                correct += correct_map.get_npoints(key)
             except Exception:
-                log.error('key=%s, correct_map = %s', key, self.correct_map)
+                log.error('key=%s, correct_map = %s', key, correct_map)
                 raise
 
-        if (not self.student_answers) or len(self.student_answers) == 0:
-            return {'score': 0,
-                    'total': self.get_max_score()}
-        else:
-            return {'score': correct,
-                    'total': self.get_max_score()}
+        return {'score': correct, 'total': self.get_max_score()}
 
     def update_score(self, score_msg, queuekey):
         """
@@ -397,7 +396,9 @@ class LoncapaProblem(object):
 
         # if answers include File objects, convert them to filenames.
         self.student_answers = convert_files_to_filenames(answers)
-        return self._grade_answers(answers)
+        new_cmap = self.get_grade_from_current_answers(answers)
+        self.correct_map = new_cmap
+        return self.correct_map
 
     def supports_rescoring(self):
         """
@@ -418,16 +419,10 @@ class LoncapaProblem(object):
         """
         return all('filesubmission' not in responder.allowed_inputfields for responder in self.responders.values())
 
-    def rescore_existing_answers(self):
+    def get_grade_from_current_answers(self, student_answers):
         """
-        Rescore student responses.  Called by capa_module.rescore_problem.
-        """
-        return self._grade_answers(None)
-
-    def _grade_answers(self, student_answers):
-        """
-        Internal grading call used for checking new 'student_answers' and also
-        rescoring existing student_answers.
+        Gets the grade for the currently-saved problem state, but does not save it
+        to the block.
 
         For new student_answers being graded, `student_answers` is a dict of all the
         entries from request.POST, but with the first part of each key removed
@@ -462,7 +457,6 @@ class LoncapaProblem(object):
                 results = responder.evaluate_answers(self.student_answers, oldcmap)
             newcmap.update(results)
 
-        self.correct_map = newcmap
         return newcmap
 
     def get_question_answers(self):
diff --git a/common/lib/xmodule/xmodule/capa_base.py b/common/lib/xmodule/xmodule/capa_base.py
index f778316bfb..06b03ff099 100644
--- a/common/lib/xmodule/xmodule/capa_base.py
+++ b/common/lib/xmodule/xmodule/capa_base.py
@@ -24,6 +24,7 @@ from capa.inputtypes import Status
 from capa.responsetypes import StudentInputError, ResponseError, LoncapaProblemError
 from capa.util import convert_files_to_filenames, get_inner_html_from_xpath
 from xblock.fields import Boolean, Dict, Float, Integer, Scope, String, XMLString
+from xblock.scorable import ScorableXBlockMixin, Score
 from xmodule.capa_base_constants import RANDOMIZATION, SHOWANSWER, SHOW_CORRECTNESS
 from xmodule.exceptions import NotFoundError
 from .fields import Date, Timedelta
@@ -219,7 +220,7 @@ class CapaFields(object):
     )
 
 
-class CapaMixin(CapaFields):
+class CapaMixin(ScorableXBlockMixin, CapaFields):
     """
         Core logic for Capa Problem, which can be used by XModules or XBlocks.
     """
@@ -290,6 +291,8 @@ class CapaMixin(CapaFields):
 
             self.set_state_from_lcp()
 
+        self.set_score(self.score_from_lcp())
+
         assert self.seed is not None
 
     def choose_new_seed(self):
@@ -372,32 +375,28 @@ class CapaMixin(CapaFields):
         """
         self.last_submission_time = datetime.datetime.now(utc)
 
-    def get_score(self):
-        """
-        Access the problem's score
-        """
-        return self.lcp.get_score()
-
     def get_progress(self):
         """
-        For now, just return score / max_score
+        For now, just return weighted earned / weighted possible
         """
-        score_dict = self.get_score()
-        score = score_dict['score']
-        total = score_dict['total']
+        score = self.get_score()
+        raw_earned = score.raw_earned
+        raw_possible = score.raw_possible
 
-        if total > 0:
+        if raw_possible > 0:
             if self.weight is not None:
                 # Progress objects expect total > 0
                 if self.weight == 0:
                     return None
 
                 # scale score and total by weight/total:
-                score = score * self.weight / total
-                total = self.weight
-
+                weighted_earned = raw_earned * self.weight / raw_possible
+                weighted_possible = self.weight
+            else:
+                weighted_earned = raw_earned
+                weighted_possible = raw_possible
             try:
-                return Progress(score, total)
+                return Progress(weighted_earned, weighted_possible)
             except (TypeError, ValueError):
                 log.exception("Got bad progress")
                 return None
@@ -572,7 +571,7 @@ class CapaMixin(CapaFields):
             # Next, generate a fresh LoncapaProblem
             self.lcp = self.new_lcp(None)
             self.set_state_from_lcp()
-
+            self.set_score(self.score_from_lcp())
             # Prepend a scary warning to the student
             _ = self.runtime.service(self, "i18n").ugettext
             warning_msg = _("Warning: The problem has been reset to its initial state!")
@@ -879,8 +878,7 @@ class CapaMixin(CapaFields):
         """
         True iff full points
         """
-        score_dict = self.get_score()
-        return score_dict['score'] == score_dict['total']
+        return self.score.raw_earned == self.score.raw_possible
 
     def answer_available(self):
         """
@@ -949,6 +947,7 @@ class CapaMixin(CapaFields):
         score_msg = data['xqueue_body']
         self.lcp.update_score(score_msg, queuekey)
         self.set_state_from_lcp()
+        self.set_score(self.score_from_lcp())
         self.publish_grade()
 
         return dict()  # No AJAX return is needed
@@ -1132,18 +1131,17 @@ class CapaMixin(CapaFields):
         """
         Publishes the student's current grade to the system as an event
         """
-        score = self.lcp.get_score()
         self.runtime.publish(
             self,
             'grade',
             {
-                'value': score['score'],
-                'max_value': score['total'],
+                'value': self.score.raw_earned,
+                'max_value': self.score.raw_possible,
                 'only_if_higher': only_if_higher,
             }
         )
 
-        return {'grade': score['score'], 'max_grade': score['total']}
+        return {'grade': self.score.raw_earned, 'max_grade': self.score.raw_possible}
 
     # pylint: disable=too-many-statements
     def submit_problem(self, data, override_time=False):
@@ -1216,6 +1214,7 @@ class CapaMixin(CapaFields):
             self.attempts = self.attempts + 1
             self.lcp.done = True
             self.set_state_from_lcp()
+            self.set_score(self.score_from_lcp())
             self.set_last_submission_time()
 
         except (StudentInputError, ResponseError, LoncapaProblemError) as inst:
@@ -1227,6 +1226,7 @@ class CapaMixin(CapaFields):
 
             # Save the user's state before failing
             self.set_state_from_lcp()
+            self.set_score(self.score_from_lcp())
 
             # If the user is a staff member, include
             # the full exception, including traceback,
@@ -1245,6 +1245,7 @@ class CapaMixin(CapaFields):
         except Exception as err:
             # Save the user's state before failing
             self.set_state_from_lcp()
+            self.set_score(self.score_from_lcp())
 
             if self.runtime.DEBUG:
                 msg = u"Error checking problem: {}".format(err.message)
@@ -1457,93 +1458,6 @@ class CapaMixin(CapaFields):
 
         return input_metadata
 
-    def rescore_problem(self, only_if_higher):
-        """
-        Checks whether the existing answers to a problem are correct.
-
-        This is called when the correct answer to a problem has been changed,
-        and the grade should be re-evaluated.
-
-        If only_if_higher is True, the answer and grade are updated
-        only if the resulting score is higher than before.
-
-        Returns a dict with one key:
-            {'success' : 'correct' | 'incorrect' | AJAX alert msg string }
-
-        Raises NotFoundError if called on a problem that has not yet been
-        answered, or NotImplementedError if it's a problem that cannot be rescored.
-
-        Returns the error messages for exceptions occurring while performing
-        the rescoring, rather than throwing them.
-        """
-        event_info = {'state': self.lcp.get_state(), 'problem_id': self.location.to_deprecated_string()}
-
-        _ = self.runtime.service(self, "i18n").ugettext
-
-        if not self.lcp.supports_rescoring():
-            event_info['failure'] = 'unsupported'
-            self.track_function_unmask('problem_rescore_fail', event_info)
-            # pylint: disable=line-too-long
-            # Translators: 'rescoring' refers to the act of re-submitting a student's solution so it can get a new score.
-            raise NotImplementedError(_("Problem's definition does not support rescoring."))
-            # pylint: enable=line-too-long
-
-        if not self.done:
-            event_info['failure'] = 'unanswered'
-            self.track_function_unmask('problem_rescore_fail', event_info)
-            raise NotFoundError(_("Problem must be answered before it can be graded again."))
-
-        # get old score, for comparison:
-        orig_score = self.lcp.get_score()
-        event_info['orig_score'] = orig_score['score']
-        event_info['orig_total'] = orig_score['total']
-
-        try:
-            correct_map = self.lcp.rescore_existing_answers()
-
-        except (StudentInputError, ResponseError, LoncapaProblemError) as inst:
-            log.warning("Input error in capa_module:problem_rescore", exc_info=True)
-            event_info['failure'] = 'input_error'
-            self.track_function_unmask('problem_rescore_fail', event_info)
-            return {'success': u"Error: {0}".format(inst.message)}
-
-        except Exception as err:
-            event_info['failure'] = 'unexpected'
-            self.track_function_unmask('problem_rescore_fail', event_info)
-            if self.runtime.DEBUG:
-                msg = u"Error checking problem: {0}".format(err.message)
-                msg += u'\nTraceback:\n' + traceback.format_exc()
-                return {'success': msg}
-            raise
-
-        # rescoring should have no effect on attempts, so don't
-        # need to increment here, or mark done.  Just save.
-        self.set_state_from_lcp()
-        self.publish_grade(only_if_higher)
-
-        new_score = self.lcp.get_score()
-        event_info['new_score'] = new_score['score']
-        event_info['new_total'] = new_score['total']
-
-        # success = correct if ALL questions in this problem are correct
-        success = 'correct'
-        for answer_id in correct_map:
-            if not correct_map.is_correct(answer_id):
-                success = 'incorrect'
-
-        # NOTE: We are logging both full grading and queued-grading submissions. In the latter,
-        #       'success' will always be incorrect
-        event_info['correct_map'] = correct_map.get_dict()
-        event_info['success'] = success
-        event_info['attempts'] = self.attempts
-        self.track_function_unmask('problem_rescore', event_info)
-
-        return {
-            'success': success,
-            'new_raw_earned': new_score['score'],
-            'new_raw_possible': new_score['total'],
-        }
-
     def save_problem(self, data):
         """
         Save the passed in answers.
@@ -1584,6 +1498,7 @@ class CapaMixin(CapaFields):
         self.lcp.has_saved_answers = True
 
         self.set_state_from_lcp()
+        self.set_score(self.score_from_lcp())
 
         self.track_function_unmask('save_problem_success', event_info)
         msg = _("Your answers have been saved.")
@@ -1642,6 +1557,7 @@ class CapaMixin(CapaFields):
 
         # Pull in the new problem seed
         self.set_state_from_lcp()
+        self.set_score(self.score_from_lcp())
 
         # Grade may have changed, so publish new value
         self.publish_grade()
@@ -1653,3 +1569,116 @@ class CapaMixin(CapaFields):
             'success': True,
             'html': self.get_problem_html(encapsulate=False),
         }
+
+    # ScorableXBlockMixin methods
+
+    def rescore(self, only_if_higher=False):
+        """
+        Checks whether the existing answers to a problem are correct.
+
+        This is called when the correct answer to a problem has been changed,
+        and the grade should be re-evaluated.
+
+        If only_if_higher is True, the answer and grade are updated
+        only if the resulting score is higher than before.
+
+        Returns a dict with one key:
+            {'success' : 'correct' | 'incorrect' | AJAX alert msg string }
+
+        Raises NotFoundError if called on a problem that has not yet been
+        answered, or NotImplementedError if it's a problem that cannot be rescored.
+
+        Returns the error messages for exceptions occurring while performing
+        the rescoring, rather than throwing them.
+        """
+        event_info = {'state': self.lcp.get_state(), 'problem_id': self.location.to_deprecated_string()}
+
+        _ = self.runtime.service(self, "i18n").ugettext
+
+        if not self.lcp.supports_rescoring():
+            event_info['failure'] = 'unsupported'
+            self.track_function_unmask('problem_rescore_fail', event_info)
+            # pylint: disable=line-too-long
+            # Translators: 'rescoring' refers to the act of re-submitting a student's solution so it can get a new score.
+            raise NotImplementedError(_("Problem's definition does not support rescoring."))
+            # pylint: enable=line-too-long
+
+        if not self.done:
+            event_info['failure'] = 'unanswered'
+            self.track_function_unmask('problem_rescore_fail', event_info)
+            raise NotFoundError(_("Problem must be answered before it can be graded again."))
+
+        # get old score, for comparison:
+        orig_score = self.get_score()
+        event_info['orig_score'] = orig_score.raw_earned
+        event_info['orig_total'] = orig_score.raw_possible
+
+        try:
+            calculated_score = self.calculate_score()
+
+        except (StudentInputError, ResponseError, LoncapaProblemError) as inst:
+            log.warning("Input error in capa_module:problem_rescore", exc_info=True)
+            event_info['failure'] = 'input_error'
+            self.track_function_unmask('problem_rescore_fail', event_info)
+            raise
+
+        except Exception:
+            event_info['failure'] = 'unexpected'
+            self.track_function_unmask('problem_rescore_fail', event_info)
+            raise
+
+        # rescoring should have no effect on attempts, so don't
+        # need to increment here, or mark done.  Just save.
+        self.set_state_from_lcp()
+        self.set_score(calculated_score)
+        self.publish_grade(only_if_higher)
+
+        event_info['new_score'] = calculated_score.raw_earned
+        event_info['new_total'] = calculated_score.raw_possible
+
+        # success = correct if ALL questions in this problem are correct
+        success = 'correct'
+        for answer_id in self.lcp.correct_map:
+            if not self.lcp.correct_map.is_correct(answer_id):
+                success = 'incorrect'
+
+        # NOTE: We are logging both full grading and queued-grading submissions. In the latter,
+        #       'success' will always be incorrect
+        event_info['correct_map'] = self.lcp.correct_map.get_dict()
+        event_info['success'] = success
+        event_info['attempts'] = self.attempts
+        self.track_function_unmask('problem_rescore', event_info)
+
+    def has_submitted_answer(self):
+        return self.done
+
+    def set_score(self, score):
+        """
+        Sets the internal score for the problem. This is not derived directly
+        from the internal LCP in keeping with the ScorableXBlock spec.
+        """
+        self.score = score
+
+    def get_score(self):
+        """
+        Returns the score currently set on the block.
+        """
+        return self.score
+
+    def calculate_score(self):
+        """
+        Returns the score calculated from the current problem state.
+        Operates by creating a new correctness map based on the current
+        state of the LCP, and having the LCP generate a score from that.
+        """
+        new_correctness = self.lcp.get_grade_from_current_answers(None)
+        new_score = self.lcp.calculate_score(new_correctness)
+        return Score(raw_earned=new_score['score'], raw_possible=new_score['total'])
+
+    def score_from_lcp(self):
+        """
+        Returns the score associated with the correctness map
+        currently stored by the LCP.
+        """
+        lcp_score = self.lcp.calculate_score()
+        return Score(raw_earned=lcp_score['score'], raw_possible=lcp_score['total'])
diff --git a/common/lib/xmodule/xmodule/capa_module.py b/common/lib/xmodule/xmodule/capa_module.py
index 7b43c36a78..071cd1f9c7 100644
--- a/common/lib/xmodule/xmodule/capa_module.py
+++ b/common/lib/xmodule/xmodule/capa_module.py
@@ -324,6 +324,7 @@ class CapaDescriptor(CapaFields, RawDescriptor):
     hint_button = module_attr('hint_button')
     handle_problem_html_error = module_attr('handle_problem_html_error')
     handle_ungraded_response = module_attr('handle_ungraded_response')
+    has_submitted_answer = module_attr('has_submitted_answer')
     is_attempted = module_attr('is_attempted')
     is_correct = module_attr('is_correct')
     is_past_due = module_attr('is_past_due')
@@ -332,7 +333,7 @@ class CapaDescriptor(CapaFields, RawDescriptor):
     make_dict_of_responses = module_attr('make_dict_of_responses')
     new_lcp = module_attr('new_lcp')
     publish_grade = module_attr('publish_grade')
-    rescore_problem = module_attr('rescore_problem')
+    rescore = module_attr('rescore')
     reset_problem = module_attr('reset_problem')
     save_problem = module_attr('save_problem')
     set_state_from_lcp = module_attr('set_state_from_lcp')
diff --git a/common/lib/xmodule/xmodule/tests/test_capa_module.py b/common/lib/xmodule/xmodule/tests/test_capa_module.py
index 73b716de68..37b4e83a04 100644
--- a/common/lib/xmodule/xmodule/tests/test_capa_module.py
+++ b/common/lib/xmodule/xmodule/tests/test_capa_module.py
@@ -29,6 +29,7 @@ from xmodule.capa_module import CapaModule, CapaDescriptor, ComplexEncoder
 from opaque_keys.edx.locations import Location
 from xblock.field_data import DictFieldData
 from xblock.fields import ScopeIds
+from xblock.scorable import Score
 
 from . import get_test_system
 from pytz import UTC
@@ -130,9 +131,9 @@ class CapaFactory(object):
         if override_get_score:
             if correct:
                 # TODO: probably better to actually set the internal state properly, but...
-                module.get_score = lambda: {'score': 1, 'total': 1}
+                module.score = Score(raw_earned=1, raw_possible=1)
             else:
-                module.get_score = lambda: {'score': 0, 'total': 1}
+                module.score = Score(raw_earned=0, raw_possible=1)
 
         module.graded = 'False'
         return module
@@ -196,10 +197,10 @@ class CapaModuleTest(unittest.TestCase):
 
     def test_import(self):
         module = CapaFactory.create()
-        self.assertEqual(module.get_score()['score'], 0)
+        self.assertEqual(module.get_score().raw_earned, 0)
 
         other_module = CapaFactory.create()
-        self.assertEqual(module.get_score()['score'], 0)
+        self.assertEqual(module.get_score().raw_earned, 0)
         self.assertNotEqual(module.url_name, other_module.url_name,
                             "Factory should be creating unique names for each problem")
 
@@ -208,31 +209,33 @@ class CapaModuleTest(unittest.TestCase):
         Check that the factory creates correct and incorrect problems properly.
         """
         module = CapaFactory.create()
-        self.assertEqual(module.get_score()['score'], 0)
+        self.assertEqual(module.get_score().raw_earned, 0)
 
         other_module = CapaFactory.create(correct=True)
-        self.assertEqual(other_module.get_score()['score'], 1)
+        self.assertEqual(other_module.get_score().raw_earned, 1)
 
     def test_get_score(self):
         """
-        Do 1 test where the internals of get_score are properly set
-
-        @jbau Note: this obviously depends on a particular implementation of get_score, but I think this is actually
-        useful as unit-code coverage for this current implementation.  I don't see a layer where LoncapaProblem
-        is tested directly
+        Tests the internals of get_score. In keeping with the ScorableXBlock spec,
+        Capa modules store their score independently of the LCP internals, so it must
+        be explicitly updated.
         """
         student_answers = {'1_2_1': 'abcd'}
         correct_map = CorrectMap(answer_id='1_2_1', correctness="correct", npoints=0.9)
         module = CapaFactory.create(correct=True, override_get_score=False)
         module.lcp.correct_map = correct_map
         module.lcp.student_answers = student_answers
-        self.assertEqual(module.get_score()['score'], 0.9)
+        self.assertEqual(module.get_score().raw_earned, 0.0)
+        module.set_score(module.score_from_lcp())
+        self.assertEqual(module.get_score().raw_earned, 0.9)
 
         other_correct_map = CorrectMap(answer_id='1_2_1', correctness="incorrect", npoints=0.1)
         other_module = CapaFactory.create(correct=False, override_get_score=False)
         other_module.lcp.correct_map = other_correct_map
         other_module.lcp.student_answers = student_answers
-        self.assertEqual(other_module.get_score()['score'], 0.1)
+        self.assertEqual(other_module.get_score().raw_earned, 0.0)
+        other_module.set_score(other_module.score_from_lcp())
+        self.assertEqual(other_module.get_score().raw_earned, 0.1)
 
     def test_showanswer_default(self):
         """
@@ -1007,14 +1010,15 @@ class CapaModuleTest(unittest.TestCase):
         # Simulate that all answers are marked correct, no matter
         # what the input is, by patching LoncapaResponse.evaluate_answers()
         with patch('capa.responsetypes.LoncapaResponse.evaluate_answers') as mock_evaluate_answers:
-            mock_evaluate_answers.return_value = CorrectMap(CapaFactory.answer_key(), 'correct')
-            result = module.rescore_problem(only_if_higher=False)
+            mock_evaluate_answers.return_value = CorrectMap(
+                answer_id=CapaFactory.answer_key(),
+                correctness='correct',
+                npoints=1,
+            )
+            module.rescore(only_if_higher=False)
 
         # Expect that the problem is marked correct
-        self.assertEqual(result['success'], 'correct')
-
-        # Expect that we get no HTML
-        self.assertNotIn('contents', result)
+        self.assertEqual(module.is_correct(), True)
 
         # Expect that the number of attempts is not incremented
         self.assertEqual(module.attempts, 1)
@@ -1028,10 +1032,10 @@ class CapaModuleTest(unittest.TestCase):
         # what the input is, by patching LoncapaResponse.evaluate_answers()
         with patch('capa.responsetypes.LoncapaResponse.evaluate_answers') as mock_evaluate_answers:
             mock_evaluate_answers.return_value = CorrectMap(CapaFactory.answer_key(), 'incorrect')
-            result = module.rescore_problem(only_if_higher=False)
+            module.rescore(only_if_higher=False)
 
         # Expect that the problem is marked incorrect
-        self.assertEqual(result['success'], 'incorrect')
+        self.assertEqual(module.is_correct(), False)
 
         # Expect that the number of attempts is not incremented
         self.assertEqual(module.attempts, 0)
@@ -1042,7 +1046,7 @@ class CapaModuleTest(unittest.TestCase):
 
         # Try to rescore the problem, and get exception
         with self.assertRaises(xmodule.exceptions.NotFoundError):
-            module.rescore_problem(only_if_higher=False)
+            module.rescore(only_if_higher=False)
 
     def test_rescore_problem_not_supported(self):
         module = CapaFactory.create(done=True)
@@ -1051,7 +1055,7 @@ class CapaModuleTest(unittest.TestCase):
         with patch('capa.capa_problem.LoncapaProblem.supports_rescoring') as mock_supports_rescoring:
             mock_supports_rescoring.return_value = False
             with self.assertRaises(NotImplementedError):
-                module.rescore_problem(only_if_higher=False)
+                module.rescore(only_if_higher=False)
 
     def _rescore_problem_error_helper(self, exception_class):
         """Helper to allow testing all errors that rescoring might return."""
@@ -1059,13 +1063,10 @@ class CapaModuleTest(unittest.TestCase):
         module = CapaFactory.create(attempts=1, done=True)
 
         # Simulate answering a problem that raises the exception
-        with patch('capa.capa_problem.LoncapaProblem.rescore_existing_answers') as mock_rescore:
+        with patch('capa.capa_problem.LoncapaProblem.get_grade_from_current_answers') as mock_rescore:
             mock_rescore.side_effect = exception_class(u'test error \u03a9')
-            result = module.rescore_problem(only_if_higher=False)
-
-        # Expect an AJAX alert message in 'success'
-        expected_msg = u'Error: test error \u03a9'
-        self.assertEqual(result['success'], expected_msg)
+            with self.assertRaises(exception_class):
+                module.rescore(only_if_higher=False)
 
         # Expect that the number of attempts is NOT incremented
         self.assertEqual(module.attempts, 1)
diff --git a/common/lib/xmodule/xmodule/tests/test_delay_between_attempts.py b/common/lib/xmodule/xmodule/tests/test_delay_between_attempts.py
index d56876e704..0bc983d6da 100644
--- a/common/lib/xmodule/xmodule/tests/test_delay_between_attempts.py
+++ b/common/lib/xmodule/xmodule/tests/test_delay_between_attempts.py
@@ -18,6 +18,7 @@ from xmodule.capa_module import CapaModule
 from opaque_keys.edx.locations import Location
 from xblock.field_data import DictFieldData
 from xblock.fields import ScopeIds
+from xblock.scorable import Score
 
 from . import get_test_system
 from pytz import UTC
@@ -111,9 +112,9 @@ class CapaFactoryWithDelay(object):
 
         if correct:
             # Could set the internal state formally, but here we just jam in the score.
-            module.get_score = lambda: {'score': 1, 'total': 1}
+            module.score = Score(raw_earned=1, raw_possible=1)
         else:
-            module.get_score = lambda: {'score': 0, 'total': 1}
+            module.score = Score(raw_earned=0, raw_possible=1)
 
         return module
 
diff --git a/lms/djangoapps/grades/signals/handlers.py b/lms/djangoapps/grades/signals/handlers.py
index 48326feadf..4bddf05829 100644
--- a/lms/djangoapps/grades/signals/handlers.py
+++ b/lms/djangoapps/grades/signals/handlers.py
@@ -2,6 +2,7 @@
 Grades related signals.
 """
 from contextlib import contextmanager
+from crum import get_current_user
 from logging import getLogger
 
 from django.dispatch import receiver
@@ -32,6 +33,8 @@ from ..tasks import recalculate_subsection_grade_v3, RECALCULATE_GRADE_DELAY
 
 log = getLogger(__name__)
 
+# define values to be used in grading events
+GRADES_RESCORE_EVENT_TYPE = 'edx.grades.problem.rescored'
 PROBLEM_SUBMITTED_EVENT_TYPE = 'edx.grades.problem.submitted'
 
 
@@ -209,7 +212,7 @@ def enqueue_subsection_update(sender, **kwargs):  # pylint: disable=unused-argum
     Handles the PROBLEM_WEIGHTED_SCORE_CHANGED signal by
     enqueueing a subsection update operation to occur asynchronously.
     """
-    _emit_problem_submitted_event(kwargs)
+    _emit_event(kwargs)
     result = recalculate_subsection_grade_v3.apply_async(
         kwargs=dict(
             user_id=kwargs['user_id'],
@@ -241,12 +244,14 @@ def recalculate_course_grade(sender, course, course_structure, user, **kwargs):
     CourseGradeFactory().update(user, course=course, course_structure=course_structure)
 
 
-def _emit_problem_submitted_event(kwargs):
+def _emit_event(kwargs):
     """
-    Emits a problem submitted event only if
-    there is no current event transaction type,
-    i.e. we have not reached this point in the
-    code via a rescore or student state deletion.
+    Emits a problem submitted event only if there is no current event
+    transaction type, i.e. we have not reached this point in the code via a
+    rescore or student state deletion.
+
+    If the event transaction type has already been set and the transacation is
+    a rescore, emits a problem rescored event.
     """
     root_type = get_event_transaction_type()
 
@@ -267,3 +272,24 @@ def _emit_problem_submitted_event(kwargs):
                 'weighted_possible': kwargs.get('weighted_possible'),
             }
         )
+
+    if root_type == 'edx.grades.problem.rescored':
+        current_user = get_current_user()
+        if current_user is not None and hasattr(current_user, 'id'):
+            instructor_id = unicode(current_user.id)
+        else:
+            instructor_id = None
+        tracker.emit(
+            unicode(GRADES_RESCORE_EVENT_TYPE),
+            {
+                'course_id': unicode(kwargs['course_id']),
+                'user_id': unicode(kwargs['user_id']),
+                'problem_id': unicode(kwargs['usage_id']),
+                'new_weighted_earned': kwargs.get('weighted_earned'),
+                'new_weighted_possible': kwargs.get('weighted_possible'),
+                'only_if_higher': kwargs.get('only_if_higher'),
+                'instructor_id': instructor_id,
+                'event_transaction_id': unicode(get_event_transaction_id()),
+                'event_transaction_type': unicode(GRADES_RESCORE_EVENT_TYPE),
+            }
+        )
diff --git a/lms/djangoapps/grades/tests/integration/test_events.py b/lms/djangoapps/grades/tests/integration/test_events.py
index 2e5a6a8e2e..bd062841c7 100644
--- a/lms/djangoapps/grades/tests/integration/test_events.py
+++ b/lms/djangoapps/grades/tests/integration/test_events.py
@@ -160,10 +160,9 @@ class GradesEventIntegrationTest(ProblemSubmissionTestMixin, SharedModuleStoreTe
             }
         )
 
-    @patch('lms.djangoapps.instructor_task.tasks_helper.module_state.tracker')
     @patch('lms.djangoapps.grades.signals.handlers.tracker')
     @patch('lms.djangoapps.grades.models.tracker')
-    def test_rescoring_events(self, models_tracker, handlers_tracker, instructor_task_tracker):
+    def test_rescoring_events(self, models_tracker, handlers_tracker):
         # submit answer
         self.submit_question_answer('p1', {'2_1': 'choice_choice_3'})
         models_tracker.reset_mock()
@@ -187,11 +186,8 @@ class GradesEventIntegrationTest(ProblemSubmissionTestMixin, SharedModuleStoreTe
         )
         # check logging to make sure id's are tracked correctly across
         # events
-        event_transaction_id = instructor_task_tracker.emit.mock_calls[0][1][1]['event_transaction_id']
-        self.assertEqual(
-            instructor_task_tracker.get_tracker().context.call_args[0],
-            ('edx.grades.problem.rescored', {'course_id': unicode(self.course.id), 'org_id': unicode(self.course.org)})
-        )
+        event_transaction_id = handlers_tracker.emit.mock_calls[0][1][1]['event_transaction_id']
+
         # make sure the id is propagated throughout the event flow
         for call in models_tracker.emit.mock_calls:
             self.assertEqual(event_transaction_id, call[1][1]['event_transaction_id'])
@@ -206,7 +202,7 @@ class GradesEventIntegrationTest(ProblemSubmissionTestMixin, SharedModuleStoreTe
 
         handlers_tracker.assert_not_called()
 
-        instructor_task_tracker.emit.assert_called_with(
+        handlers_tracker.emit.assert_called_with(
             unicode(RESCORE_TYPE),
             {
                 'course_id': unicode(self.course.id),
diff --git a/lms/djangoapps/instructor_task/api_helper.py b/lms/djangoapps/instructor_task/api_helper.py
index 506b636219..0523db6425 100644
--- a/lms/djangoapps/instructor_task/api_helper.py
+++ b/lms/djangoapps/instructor_task/api_helper.py
@@ -100,6 +100,17 @@ def _get_xmodule_instance_args(request, task_id):
     return xmodule_instance_args
 
 
+def _supports_rescore(descriptor):
+    """
+    Helper method to determine whether a given item supports rescoring.
+    In order to accommodate both XModules and XBlocks, we have to check
+    the descriptor itself then fall back on its module class.
+    """
+    return hasattr(descriptor, 'rescore') or (
+        hasattr(descriptor, 'module_class') and hasattr(descriptor.module_class, 'rescore')
+    )
+
+
 def _update_instructor_task(instructor_task, task_result):
     """
     Updates and possibly saves a InstructorTask entry based on a task Result.
@@ -246,10 +257,7 @@ def check_arguments_for_rescoring(usage_key):
     corresponding module doesn't support rescoring calls.
     """
     descriptor = modulestore().get_item(usage_key)
-    # TODO: Clean this up as part of TNL-6594 when CAPA uses the ScorableXBlockMixin
-    if (
-            not hasattr(descriptor, 'module_class') or not hasattr(descriptor.module_class, 'rescore_problem')
-    ) and not hasattr(descriptor, 'rescore'):
+    if not _supports_rescore(descriptor):
         msg = "Specified module does not support rescoring."
         raise NotImplementedError(msg)
 
@@ -264,8 +272,7 @@ def check_entrance_exam_problems_for_rescoring(exam_key):  # pylint: disable=inv
     any of the problem in entrance exam doesn't support re-scoring calls.
     """
     problems = get_problems_in_section(exam_key).values()
-    if any(not hasattr(problem, 'module_class') or not hasattr(problem.module_class, 'rescore_problem')
-           for problem in problems):
+    if any(not _supports_rescore(problem) for problem in problems):
         msg = _("Not all problems in entrance exam support re-scoring.")
         raise NotImplementedError(msg)
 
diff --git a/lms/djangoapps/instructor_task/tasks_helper/module_state.py b/lms/djangoapps/instructor_task/tasks_helper/module_state.py
index b01402946c..a5775d1a04 100644
--- a/lms/djangoapps/instructor_task/tasks_helper/module_state.py
+++ b/lms/djangoapps/instructor_task/tasks_helper/module_state.py
@@ -10,6 +10,7 @@ from time import time
 from eventtracking import tracker
 from opaque_keys.edx.keys import UsageKey
 from xmodule.modulestore.django import modulestore
+from capa.responsetypes import StudentInputError, ResponseError, LoncapaProblemError
 from courseware.courses import get_course_by_id, get_problems_in_section
 from courseware.models import StudentModule
 from courseware.model_data import DjangoKeyValueStore, FieldDataCache
@@ -174,38 +175,28 @@ def rescore_problem_module_state(xmodule_instance_args, module_descriptor, stude
             TASK_LOG.warning(msg)
             return UPDATE_STATUS_FAILED
 
-        # TODO: (TNL-6594)  Remove this switch once rescore_problem support
-        # once CAPA uses ScorableXBlockMixin.
-        for method in ['rescore', 'rescore_problem']:
-            rescore_method = getattr(instance, method, None)
-            if rescore_method is not None:
-                break
-        else:  # for-else: Neither method exists on the block.
+        if not hasattr(instance, 'rescore'):
             # This should not happen, since it should be already checked in the
             # caller, but check here to be sure.
             msg = "Specified problem does not support rescoring."
             raise UpdateProblemModuleStateError(msg)
 
-        # TODO: Remove the first part of this if-else with TNL-6594
         # We check here to see if the problem has any submissions. If it does not, we don't want to rescore it
-        if hasattr(instance, "done"):
-            if not instance.done:
-                return UPDATE_STATUS_SKIPPED
-        elif not instance.has_submitted_answer():
-                return UPDATE_STATUS_SKIPPED
+        if not instance.has_submitted_answer():
+            return UPDATE_STATUS_SKIPPED
 
         # Set the tracking info before this call, because it makes downstream
         # calls that create events.  We retrieve and store the id here because
         # the request cache will be erased during downstream calls.
-        event_transaction_id = create_new_event_transaction_id()
+        create_new_event_transaction_id()
         set_event_transaction_type(GRADES_RESCORE_EVENT_TYPE)
 
-        result = rescore_method(only_if_higher=task_input['only_if_higher'])
-        instance.save()
-
-        if result is None or result.get(u'success') in {u'correct', u'incorrect'}:
-            TASK_LOG.debug(
-                u"successfully processed rescore call for course %(course)s, problem %(loc)s "
+        # specific events from CAPA are not propagated up the stack. Do we want this?
+        try:
+            instance.rescore(only_if_higher=task_input['only_if_higher'])
+        except (LoncapaProblemError, StudentInputError, ResponseError):
+            TASK_LOG.warning(
+                u"error processing rescore call for course %(course)s, problem %(loc)s "
                 u"and student %(student)s",
                 dict(
                     course=course_id,
@@ -213,45 +204,21 @@ def rescore_problem_module_state(xmodule_instance_args, module_descriptor, stude
                     student=student
                 )
             )
-
-            if result is not None:  # Only for CAPA. This will get moved to the grade handler.
-                new_weighted_earned, new_weighted_possible = weighted_score(
-                    result['new_raw_earned'] if result else None,
-                    result['new_raw_possible'] if result else None,
-                    module_descriptor.weight,
-                )
-
-                # TODO: remove this context manager after completion of AN-6134
-                context = course_context_from_course_id(course_id)
-                with tracker.get_tracker().context(GRADES_RESCORE_EVENT_TYPE, context):
-                    tracker.emit(
-                        unicode(GRADES_RESCORE_EVENT_TYPE),
-                        {
-                            'course_id': unicode(course_id),
-                            'user_id': unicode(student.id),
-                            'problem_id': unicode(usage_key),
-                            'new_weighted_earned': new_weighted_earned,
-                            'new_weighted_possible': new_weighted_possible,
-                            'only_if_higher': task_input['only_if_higher'],
-                            'instructor_id': unicode(xmodule_instance_args['request_info']['user_id']),
-                            'event_transaction_id': unicode(event_transaction_id),
-                            'event_transaction_type': unicode(GRADES_RESCORE_EVENT_TYPE),
-                        }
-                    )
-            return UPDATE_STATUS_SUCCEEDED
-        else:
-            TASK_LOG.warning(
-                u"error processing rescore call for course %(course)s, problem %(loc)s "
-                u"and student %(student)s: %(msg)s",
-                dict(
-                    msg=result.get('success', result),
-                    course=course_id,
-                    loc=usage_key,
-                    student=student
-                )
-            )
             return UPDATE_STATUS_FAILED
 
+        instance.save()
+        TASK_LOG.debug(
+            u"successfully processed rescore call for course %(course)s, problem %(loc)s "
+            u"and student %(student)s",
+            dict(
+                course=course_id,
+                loc=usage_key,
+                student=student
+            )
+        )
+
+        return UPDATE_STATUS_SUCCEEDED
+
 
 @outer_atomic
 def reset_attempts_module_state(xmodule_instance_args, _module_descriptor, student_module, _task_input):
diff --git a/lms/djangoapps/instructor_task/tests/test_integration.py b/lms/djangoapps/instructor_task/tests/test_integration.py
index f3c96ebd7c..cff20f783d 100644
--- a/lms/djangoapps/instructor_task/tests/test_integration.py
+++ b/lms/djangoapps/instructor_task/tests/test_integration.py
@@ -18,6 +18,7 @@ from django.contrib.auth.models import User
 from django.core.urlresolvers import reverse
 
 from openedx.core.djangoapps.util.testing import TestConditionalContent
+from openedx.core.djangolib.testing.utils import get_mock_request
 from capa.tests.response_xml_factory import (CodeResponseXMLFactory,
                                              CustomResponseXMLFactory)
 from xmodule.modulestore.tests.factories import ItemFactory
@@ -275,7 +276,7 @@ class TestRescoringTask(TestIntegrationTask):
         self.submit_student_answer('u1', problem_url_name, [OPTION_1, OPTION_1])
 
         expected_message = "bad things happened"
-        with patch('capa.capa_problem.LoncapaProblem.rescore_existing_answers') as mock_rescore:
+        with patch('capa.capa_problem.LoncapaProblem.get_grade_from_current_answers') as mock_rescore:
             mock_rescore.side_effect = ZeroDivisionError(expected_message)
             instructor_task = self.submit_rescore_all_student_answers('instructor', problem_url_name)
         self._assert_task_failure(instructor_task.id, 'rescore_problem', problem_url_name, expected_message)
@@ -293,7 +294,7 @@ class TestRescoringTask(TestIntegrationTask):
 
         # return an input error as if it were a numerical response, with an embedded unicode character:
         expected_message = u"Could not interpret '2/3\u03a9' as a number"
-        with patch('capa.capa_problem.LoncapaProblem.rescore_existing_answers') as mock_rescore:
+        with patch('capa.capa_problem.LoncapaProblem.get_grade_from_current_answers') as mock_rescore:
             mock_rescore.side_effect = StudentInputError(expected_message)
             instructor_task = self.submit_rescore_all_student_answers('instructor', problem_url_name)
 
diff --git a/lms/djangoapps/instructor_task/tests/test_tasks.py b/lms/djangoapps/instructor_task/tests/test_tasks.py
index aff1b6727b..84f119e8c9 100644
--- a/lms/djangoapps/instructor_task/tests/test_tasks.py
+++ b/lms/djangoapps/instructor_task/tests/test_tasks.py
@@ -307,30 +307,21 @@ class TestRescoreInstructorTask(TestInstructorTasks):
             action_name='rescored'
         )
 
-    @ddt.data(
-        ('rescore', None),
-        ('rescore_problem', {'success': 'correct', 'new_raw_earned': 1, 'new_raw_possible': 1})
-    )
-    @ddt.unpack
-    def test_rescoring_success(self, rescore_method, rescore_result):
+    def test_rescoring_success(self):
         """
         Tests rescores a problem in a course, for all students succeeds.
         """
         mock_instance = MagicMock()
-        other_method = ({'rescore', 'rescore_problem'} - {rescore_method}).pop()
-        getattr(mock_instance, rescore_method).return_value = rescore_result
-        delattr(mock_instance, other_method)
-
-        if rescore_method == 'rescore':
-            del mock_instance.done
-            mock_instance.has_submitted_answer.return_value = True
-        else:
-            mock_instance.done = True
+        getattr(mock_instance, 'rescore').return_value = None
+        mock_instance.has_submitted_answer.return_value = True
+        del mock_instance.done  # old CAPA code used to use this value so we delete it here to be sure
 
         num_students = 10
         self._create_students_with_state(num_students)
         task_entry = self._create_input_entry()
-        with patch('lms.djangoapps.instructor_task.tasks_helper.module_state.get_module_for_descriptor_internal') as mock_get_module:
+        with patch(
+                'lms.djangoapps.instructor_task.tasks_helper.module_state.get_module_for_descriptor_internal'
+        ) as mock_get_module:
             mock_get_module.return_value = mock_instance
             self._run_task_with_mock_celery(rescore_problem, task_entry.id, task_entry.task_id)
 
@@ -344,56 +335,6 @@ class TestRescoreInstructorTask(TestInstructorTasks):
             action_name='rescored'
         )
 
-    def test_rescoring_bad_result(self):
-        """
-        Tests and confirm that rescoring does not succeed if "success" key is not an expected value.
-        """
-        input_state = json.dumps({'done': True})
-        num_students = 10
-        self._create_students_with_state(num_students, input_state)
-        task_entry = self._create_input_entry()
-        mock_instance = Mock()
-        mock_instance.rescore_problem = Mock(return_value={'success': 'bogus'})
-        del mock_instance.rescore
-        with patch('lms.djangoapps.instructor_task.tasks_helper.module_state.get_module_for_descriptor_internal') as mock_get_module:
-            mock_get_module.return_value = mock_instance
-            self._run_task_with_mock_celery(rescore_problem, task_entry.id, task_entry.task_id)
-
-        self.assert_task_output(
-            output=self.get_task_output(task_entry.id),
-            total=num_students,
-            attempted=num_students,
-            succeeded=0,
-            skipped=0,
-            failed=num_students,
-            action_name='rescored'
-        )
-
-    def test_rescoring_missing_result(self):
-        """
-        Tests and confirm that rescoring does not succeed if "success" key is not returned.
-        """
-        input_state = json.dumps({'done': True})
-        num_students = 10
-        self._create_students_with_state(num_students, input_state)
-        task_entry = self._create_input_entry()
-        mock_instance = Mock()
-        mock_instance.rescore_problem = Mock(return_value={'bogus': 'value'})
-        del mock_instance.rescore
-        with patch('lms.djangoapps.instructor_task.tasks_helper.module_state.get_module_for_descriptor_internal') as mock_get_module:
-            mock_get_module.return_value = mock_instance
-            self._run_task_with_mock_celery(rescore_problem, task_entry.id, task_entry.task_id)
-
-        self.assert_task_output(
-            output=self.get_task_output(task_entry.id),
-            total=num_students,
-            attempted=num_students,
-            succeeded=0,
-            skipped=0,
-            failed=num_students,
-            action_name='rescored'
-        )
-
 
 @attr(shard=3)
 class TestResetAttemptsInstructorTask(TestInstructorTasks):