Better support specifying of modulestore configuration in test cases

The existing pattern of using `override_settings(MODULESTORE=...)` prevented
us from having more than one layer of subclassing in modulestore tests.

In a structure like:

    @override_settings(MODULESTORE=store_a)
    class BaseTestCase(ModuleStoreTestCase):
        def setUp(self):
            # use store

    @override_settings(MODULESTORE=store_b)
    class ChildTestCase(BaseTestCase):
        def setUp(self):
            # use store

In this case, the store actions performed in `BaseTestCase` on behalf of
`ChildTestCase` would still use `store_a`, even though the `ChildTestCase`
had specified to use `store_b`. This is because the `override_settings`
decorator would be the innermost wrapper around the `BaseTestCase.setUp` method,
no matter what `ChildTestCase` does.

To remedy this, we move the call to `override_settings` into the
`ModuleStoreTestCase.setUp` method, and use a cleanup to remove the override.
Subclasses can just defined the `MODULESTORE` class attribute to specify which
modulestore to use _for the entire `setUp` chain_.

[PLAT-419]

common/djangoapps/course_about/tests/test_api.py

@@ -17,14 +17,8 @@ from xmodule.modulestore.tests.django_utils import (
 from xmodule.modulestore.tests.factories import CourseFactory, CourseAboutFactory
 from student.tests.factories import UserFactory
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class CourseInfoTest(ModuleStoreTestCase, APITestCase):
     """

common/djangoapps/course_about/tests/test_data.py

@@ -16,12 +16,7 @@ from course_about import data
 from course_about.errors import CourseNotFoundError
 from xmodule.modulestore.django import modulestore
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
 
-
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class CourseAboutDataTest(ModuleStoreTestCase):
     """

common/djangoapps/course_about/tests/test_views.py

@@ -22,14 +22,8 @@ from course_about import api
 from course_about.errors import CourseNotFoundError, CourseAboutError
 from xmodule.modulestore.django import modulestore
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class CourseInfoTest(ModuleStoreTestCase, APITestCase):
     """

common/djangoapps/course_modes/tests/test_views.py

@@ -18,13 +18,7 @@ from student.models import CourseEnrollment
 from course_modes.models import CourseMode, Mode
 
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
-
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class CourseModeViewTest(UrlResetMixin, ModuleStoreTestCase):
     @patch.dict(settings.FEATURES, {'MODE_CREATION_FOR_TESTING': True})

common/djangoapps/embargo/tests/test_forms.py

@@ -16,7 +16,6 @@ from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import TEST_DATA_MOCK_MODULESTORE
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class EmbargoCourseFormTest(ModuleStoreTestCase):
     """Test the course form properly validates course IDs"""
 

common/djangoapps/embargo/tests/test_middleware.py

@@ -24,13 +24,7 @@ from config_models.models import cache
 from embargo.models import EmbargoedCourse, EmbargoedState, IPFilter
 
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
-
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class EmbargoMiddlewareTests(ModuleStoreTestCase):
     """

common/djangoapps/enrollment/tests/test_data.py

@@ -19,13 +19,8 @@ from student.tests.factories import UserFactory, CourseModeFactory
 from student.models import CourseEnrollment, EnrollmentClosedError, CourseFullError, AlreadyEnrolledError
 from enrollment import data
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class EnrollmentDataTest(ModuleStoreTestCase):
     """

common/djangoapps/enrollment/tests/test_views.py

@@ -20,13 +20,8 @@ from enrollment.errors import CourseEnrollmentError
 from student.tests.factories import UserFactory, CourseModeFactory
 from student.models import CourseEnrollment
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class EnrollmentTest(ModuleStoreTestCase, APITestCase):
     """

common/djangoapps/external_auth/tests/test_shib.py

@@ -73,7 +73,7 @@ def gen_all_identities():
 
 
 @ddt
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE, SESSION_ENGINE='django.contrib.sessions.backends.cache')
+@override_settings(SESSION_ENGINE='django.contrib.sessions.backends.cache')
 class ShibSPTest(ModuleStoreTestCase):
     """
     Tests for the Shibboleth SP, which communicates via request.META

common/djangoapps/geoinfo/tests/test_middleware.py

@@ -14,7 +14,6 @@ from xmodule.modulestore.tests.django_utils import TEST_DATA_MOCK_MODULESTORE
 from student.tests.factories import UserFactory, AnonymousUserFactory
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class CountryMiddlewareTests(TestCase):
     """
     Tests of CountryMiddleware.

common/djangoapps/reverification/tests/test_models.py

@@ -14,7 +14,6 @@ from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class TestMidcourseReverificationWindow(ModuleStoreTestCase):
     """ Tests for MidcourseReverificationWindow objects """
 

common/djangoapps/student/tests/test_bulk_email_settings.py

@@ -24,12 +24,12 @@ from xmodule.modulestore.tests.factories import CourseFactory
 from bulk_email.models import CourseAuthorization  # pylint: disable=import-error
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class TestStudentDashboardEmailView(ModuleStoreTestCase):
     """
     Check for email view displayed with flag
     """
+
     def setUp(self):
         super(TestStudentDashboardEmailView, self).setUp()
 
@@ -92,12 +92,13 @@ class TestStudentDashboardEmailView(ModuleStoreTestCase):
         self.assertTrue(self.email_modal_link in response.content)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MIXED_TOY_MODULESTORE)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class TestStudentDashboardEmailViewXMLBacked(ModuleStoreTestCase):
     """
     Check for email view on student dashboard, with XML backed course.
     """
+    MODULESTORE = TEST_DATA_MIXED_TOY_MODULESTORE
+
     def setUp(self):
         self.course_name = 'edX/toy/2012_Fall'
 

common/djangoapps/student/tests/test_enrollment.py

@@ -8,25 +8,19 @@ from mock import patch
 from django.test.utils import override_settings
 from django.conf import settings
 from django.core.urlresolvers import reverse
-from xmodule.modulestore.tests.django_utils import (
-    ModuleStoreTestCase, mixed_store_config
-)
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 from student.tests.factories import UserFactory, CourseModeFactory
 from student.models import CourseEnrollment
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class EnrollmentTest(ModuleStoreTestCase):
     """
     Test student enrollment, especially with different course modes.
     """
+
     USERNAME = "Bob"
     EMAIL = "bob@example.com"
     PASSWORD = "edx"

common/djangoapps/student/tests/test_login.py

@@ -319,11 +319,11 @@ class LoginTest(TestCase):
             self.assertNotIn(log_string, format_string)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class ExternalAuthShibTest(ModuleStoreTestCase):
     """
     Tests how login_user() interacts with ExternalAuth, in particular Shib
     """
+
     def setUp(self):
         super(ExternalAuthShibTest, self).setUp()
         self.course = CourseFactory.create(

common/djangoapps/student/tests/test_login_registration_forms.py

@@ -12,9 +12,7 @@ from django.test.utils import override_settings
 from util.testing import UrlResetMixin
 from xmodule.modulestore.tests.factories import CourseFactory
 from student.tests.factories import CourseModeFactory
-from xmodule.modulestore.tests.django_utils import (
-    ModuleStoreTestCase, mixed_store_config
-)
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 
 # This relies on third party auth being enabled and configured
@@ -23,10 +21,6 @@ from xmodule.modulestore.tests.django_utils import (
 THIRD_PARTY_AUTH_BACKENDS = ["google-oauth2", "facebook"]
 THIRD_PARTY_AUTH_PROVIDERS = ["Google", "Facebook"]
 
-# Since we don't need any XML course fixtures, use a modulestore configuration
-# that disables the XML modulestore.
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 
 def _third_party_login_url(backend_name, auth_entry, course_id=None, redirect_url=None):
     """Construct the login URL to start third party authentication. """
@@ -43,7 +37,6 @@ def _third_party_login_url(backend_name, auth_entry, course_id=None, redirect_ur
 
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class LoginFormTest(UrlResetMixin, ModuleStoreTestCase):
     """Test rendering of the login form. """
@@ -156,7 +149,6 @@ class LoginFormTest(UrlResetMixin, ModuleStoreTestCase):
 
 
 @ddt.ddt
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class RegisterFormTest(UrlResetMixin, ModuleStoreTestCase):
     """Test rendering of the registration form. """

common/djangoapps/student/tests/test_verification_status.py

@@ -17,17 +17,13 @@ from student.helpers import (
 )
 
 from xmodule.modulestore.tests.factories import CourseFactory
-from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase, mixed_store_config
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from student.tests.factories import UserFactory, CourseEnrollmentFactory
 from course_modes.tests.factories import CourseModeFactory
 from verify_student.models import SoftwareSecurePhotoVerification  # pylint: disable=F0401
 from util.testing import UrlResetMixin
 
 
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
-
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @patch.dict(settings.FEATURES, {'AUTOMATIC_VERIFY_STUDENT_IDENTITY_FOR_TESTING': True})
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 @ddt.ddt

common/djangoapps/student/tests/tests.py

@@ -28,7 +28,6 @@ from student.views import (process_survey_link, _cert_info,
 from student.tests.factories import UserFactory, CourseModeFactory
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
-from xmodule.modulestore.tests.django_utils import TEST_DATA_MOCK_MODULESTORE
 
 # These imports refer to lms djangoapps.
 # Their testcases are only run under lms.
@@ -180,7 +179,6 @@ class CourseEndingTest(TestCase):
         self.assertIsNone(_cert_info(user, course2, cert_status))
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class DashboardTest(ModuleStoreTestCase):
     """
     Tests for dashboard utility functions
@@ -615,7 +613,6 @@ class EnrollInCourseTest(TestCase):
         self.assert_enrollment_mode_change_event_was_emitted(user, course_id, "honor")
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 @unittest.skipUnless(settings.ROOT_URLCONF == 'lms.urls', 'Test only valid in lms')
 class ChangeEnrollmentViewTest(ModuleStoreTestCase):
     """Tests the student.views.change_enrollment view"""
@@ -698,7 +695,6 @@ class ChangeEnrollmentViewTest(ModuleStoreTestCase):
         self.assertEqual(enrollment_mode, u'honor')
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class PaidRegistrationTest(ModuleStoreTestCase):
     """
     Tests for paid registration functionality (not verified student), involves shoppingcart
@@ -731,7 +727,6 @@ class PaidRegistrationTest(ModuleStoreTestCase):
             shoppingcart.models.Order.get_cart_for_user(self.user), self.course.id))
 
 
-@override_settings(MODULESTORE=TEST_DATA_MOCK_MODULESTORE)
 class AnonymousLookupTable(ModuleStoreTestCase):
     """
     Tests for anonymous_id_functions

common/djangoapps/third_party_auth/tests/test_change_enrollment.py

@@ -16,14 +16,10 @@ from django.test.utils import override_settings
 from xmodule.modulestore.tests.factories import CourseFactory
 from student.tests.factories import UserFactory, CourseModeFactory
 from student.models import CourseEnrollment
-from xmodule.modulestore.tests.django_utils import (
-    ModuleStoreTestCase, mixed_store_config
-)
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from openedx.core.djangoapps.user_api.models import UserOrgTag
 
 
-MODULESTORE_CONFIG = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {}, include_xml=False)
-
 THIRD_PARTY_AUTH_CONFIGURED = (
     settings.FEATURES.get('ENABLE_THIRD_PARTY_AUTH') and
     getattr(settings, 'THIRD_PARTY_AUTH', {})
@@ -31,7 +27,6 @@ THIRD_PARTY_AUTH_CONFIGURED = (
 
 
 @unittest.skipUnless(THIRD_PARTY_AUTH_CONFIGURED, "Third party auth must be configured")
-@override_settings(MODULESTORE=MODULESTORE_CONFIG)
 @ddt.ddt
 class PipelineEnrollmentTest(ModuleStoreTestCase):
     """Test that the pipeline auto-enrolls students upon successful authentication. """