@@ -184,7 +183,7 @@ class CapaHtmlRenderTest(unittest.TestCase):
xml_str = CustomResponseXMLFactory().build_xml(**kwargs)
# Create the problem and render the html
- problem = LoncapaProblem(xml_str, '1', system=test_system)
+ problem = new_loncapa_problem(xml_str)
# Grade the problem
correctmap = problem.grade_answers({'1_2_1': 'test'})
@@ -219,7 +218,7 @@ class CapaHtmlRenderTest(unittest.TestCase):
""")
# Create the problem and render the HTML
- problem = LoncapaProblem(xml_str, '1', system=test_system)
+ problem = new_loncapa_problem(xml_str)
rendered_html = etree.XML(problem.get_html())
# Expect that the variable $test has been replaced with its value
diff --git a/common/lib/capa/capa/tests/test_responsetypes.py b/common/lib/capa/capa/tests/test_responsetypes.py
index 8e41ff39de..9cafef23d6 100644
--- a/common/lib/capa/capa/tests/test_responsetypes.py
+++ b/common/lib/capa/capa/tests/test_responsetypes.py
@@ -12,9 +12,8 @@ import textwrap
import mock
import textwrap
-from . import test_system
+from . import new_loncapa_problem
-import capa.capa_problem as lcp
from capa.responsetypes import LoncapaProblemError, \
StudentInputError, ResponseError
from capa.correctmap import CorrectMap
@@ -33,7 +32,7 @@ class ResponseTest(unittest.TestCase):
def build_problem(self, **kwargs):
xml = self.xml_factory.build_xml(**kwargs)
- return lcp.LoncapaProblem(xml, '1', system=test_system)
+ return new_loncapa_problem(xml)
def assert_grade(self, problem, submission, expected_correctness, msg=None):
input_dict = {'1_2_1': submission}
diff --git a/common/lib/xmodule/xmodule/capa_module.py b/common/lib/xmodule/xmodule/capa_module.py
index 4143345196..ec0c3c8619 100644
--- a/common/lib/xmodule/xmodule/capa_module.py
+++ b/common/lib/xmodule/xmodule/capa_module.py
@@ -3,7 +3,9 @@ import datetime
import hashlib
import json
import logging
+import os
import traceback
+import struct
import sys
from pkg_resources import resource_string
@@ -23,8 +25,10 @@ from xmodule.util.date_utils import time_to_datetime
log = logging.getLogger("mitx.courseware")
-# Generated this many different variants of problems with rerandomize=per_student
+# Generate this many different variants of problems with rerandomize=per_student
NUM_RANDOMIZATION_BINS = 20
+# Never produce more than this many different seeds, no matter what.
+MAX_RANDOMIZATION_BINS = 1000
def randomization_bin(seed, problem_id):
@@ -108,11 +112,7 @@ class CapaModule(CapaFields, XModule):
self.close_date = due_date
if self.seed is None:
- if self.rerandomize == 'never':
- self.seed = 1
- elif self.rerandomize == "per_student" and hasattr(self.system, 'seed'):
- # see comment on randomization_bin
- self.seed = randomization_bin(system.seed, self.location.url)
+ self.choose_new_seed()
# Need the problem location in openendedresponse to send out. Adding
# it to the system here seems like the least clunky way to get it
@@ -156,6 +156,22 @@ class CapaModule(CapaFields, XModule):
self.set_state_from_lcp()
+ assert self.seed is not None
+
+ def choose_new_seed(self):
+ """Choose a new seed."""
+ if self.rerandomize == 'never':
+ self.seed = 1
+ elif self.rerandomize == "per_student" and hasattr(self.system, 'seed'):
+ # see comment on randomization_bin
+ self.seed = randomization_bin(self.system.seed, self.location.url)
+ else:
+ self.seed = struct.unpack('i', os.urandom(4))[0]
+
+ # So that sandboxed code execution can be cached, but still have an interesting
+ # number of possibilities, cap the number of different random seeds.
+ self.seed %= MAX_RANDOMIZATION_BINS
+
def new_lcp(self, state, text=None):
if text is None:
text = self.data
@@ -164,6 +180,7 @@ class CapaModule(CapaFields, XModule):
problem_text=text,
id=self.location.html_id(),
state=state,
+ seed=self.seed,
system=self.system,
)
@@ -831,14 +848,11 @@ class CapaModule(CapaFields, XModule):
'error': "Refresh the page and make an attempt before resetting."}
if self.rerandomize in ["always", "onreset"]:
- # reset random number generator seed (note the self.lcp.get_state()
- # in next line)
- seed = None
- else:
- seed = self.lcp.seed
+ # Reset random number generator seed.
+ self.choose_new_seed()
# Generate a new problem with either the previous seed or a new seed
- self.lcp = self.new_lcp({'seed': seed})
+ self.lcp = self.new_lcp(None)
# Pull in the new problem seed
self.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 f948f5bdfe..61de21b129 100644
--- a/common/lib/xmodule/xmodule/tests/test_capa_module.py
+++ b/common/lib/xmodule/xmodule/tests/test_capa_module.py
@@ -550,6 +550,7 @@ class CapaModuleTest(unittest.TestCase):
def test_reset_problem(self):
module = CapaFactory.create(done=True)
module.new_lcp = Mock(wraps=module.new_lcp)
+ module.choose_new_seed = Mock(wraps=module.choose_new_seed)
# Stub out HTML rendering
with patch('xmodule.capa_module.CapaModule.get_problem_html') as mock_html:
@@ -567,7 +568,8 @@ class CapaModuleTest(unittest.TestCase):
self.assertEqual(result['html'], "
Test HTML
")
# Expect that the problem was reset
- module.new_lcp.assert_called_once_with({'seed': None})
+ module.new_lcp.assert_called_once_with(None)
+ module.choose_new_seed.assert_called_once_with()
def test_reset_problem_closed(self):
module = CapaFactory.create()
@@ -1033,3 +1035,13 @@ class CapaModuleTest(unittest.TestCase):
self.assertTrue(module.seed is not None)
msg = 'Could not get a new seed from reset after 5 tries'
self.assertTrue(success, msg)
+
+ def test_random_seed_bins(self):
+ # Assert that we are limiting the number of possible seeds.
+
+ # Check the conditions that generate random seeds
+ for rerandomize in ['always', 'per_student', 'true', 'onreset']:
+ # Get a bunch of seeds, they should all be in 0-999.
+ for i in range(200):
+ module = CapaFactory.create(rerandomize=rerandomize)
+ assert 0 <= module.seed < 1000