Ensure that external projects do not need to add 'djangorestframework.tests' to…

Ensure that external projects do not need to add 'djangorestframework.tests' to INSTALLED_APPS during testing.

djangorestframework/tests/testcases.py

+# http://djangosnippets.org/snippets/1011/
+from django.conf import settings
+from django.core.management import call_command
+from django.db.models import loading
+from django.test import TestCase
+
+NO_SETTING = ('!', None)
+
+class TestSettingsManager(object):
+    """
+    A class which can modify some Django settings temporarily for a
+    test and then revert them to their original values later.
+
+    Automatically handles resyncing the DB if INSTALLED_APPS is
+    modified.
+
+    """
+    def __init__(self):
+        self._original_settings = {}
+
+    def set(self, **kwargs):
+        for k,v in kwargs.iteritems():
+            self._original_settings.setdefault(k, getattr(settings, k,
+                                                          NO_SETTING))
+            setattr(settings, k, v)
+        if 'INSTALLED_APPS' in kwargs:
+            self.syncdb()
+
+    def syncdb(self):
+        loading.cache.loaded = False
+        call_command('syncdb', verbosity=0)
+
+    def revert(self):
+        for k,v in self._original_settings.iteritems():
+            if v == NO_SETTING:
+                delattr(settings, k)
+            else:
+                setattr(settings, k, v)
+        if 'INSTALLED_APPS' in self._original_settings:
+            self.syncdb()
+        self._original_settings = {}
+
+
+class SettingsTestCase(TestCase):
+    """
+    A subclass of the Django TestCase with a settings_manager
+    attribute which is an instance of TestSettingsManager.
+
+    Comes with a tearDown() method that calls
+    self.settings_manager.revert().
+
+    """
+    def __init__(self, *args, **kwargs):
+        super(SettingsTestCase, self).__init__(*args, **kwargs)
+        self.settings_manager = TestSettingsManager()
+    
+    def tearDown(self):
+        self.settings_manager.revert()
+
+class TestModelsTestCase(SettingsTestCase):
+    def setUp(self, *args, **kwargs):
+        installed_apps = tuple(settings.INSTALLED_APPS) + ('djangorestframework.tests',)
+        self.settings_manager.set(INSTALLED_APPS=installed_apps)
\ No newline at end of file