Switch to pytest for unit tests

common/lib/conftest.py

@@ -0,0 +1,8 @@
+from django.conf import settings
+
+
+def pytest_configure():
+    """
+    Use Django's default settings for tests in common/lib.
+    """
+    settings.configure()

common/lib/pytest.ini

@@ -0,0 +1,5 @@
+[pytest]
+addopts = --nomigrations --reuse-db --durations=20
+norecursedirs = .cache
+python_classes =
+python_files = tests.py test_*.py tests_*.py *_tests.py __init__.py

common/lib/xmodule/xmodule/modulestore/tests/test_split_modulestore.py

@@ -13,12 +13,6 @@ import uuid
 import ddt
 from contracts import contract
 from nose.plugins.attrib import attr
-# For the cache tests to work, we need to be using the Django default
-# settings (not our usual cms or lms test settings) and they need to
-# be configured before importing from django.core.cache
-from django.conf import settings
-if not settings.configured:
-    settings.configure()
 from django.core.cache import caches, InvalidCacheBackendError
 
 from openedx.core.lib import tempdir