Fixed #8138 -- Changed django.test.TestCase to rollback tests (when the database supports it) instead of flushing and reloading the database. This can substantially reduce the time it takes to run large test suites.

This change may be slightly backwards incompatible, if existing tests need to test transactional behavior, or if they rely on invalid assumptions or a specific test case ordering.  For the first case, django.test.TransactionTestCase should be used.  TransactionTestCase is also a quick fix to get around test case errors revealed by the new rollback approach, but a better long-term fix is to correct the test case.  See the testing doc for full details.

Many thanks to:
* Marc Remolt for the initial proposal and implementation.
* Luke Plant for initial testing and improving the implementation.
* Ramiro Morales for feedback and help with tracking down a mysterious PostgreSQL issue.
* Eric Holscher for feedback regarding the effect of the change on the Ellington testsuite.
* Russell Keith-Magee for guidance and feedback from beginning to end.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9756 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/test/testcases.py

@@ -7,7 +7,7 @@ from django.conf import settings
 from django.core import mail
 from django.core.management import call_command
 from django.core.urlresolvers import clear_url_caches
-from django.db import transaction
+from django.db import transaction, connection
 from django.http import QueryDict
 from django.test import _doctest as doctest
 from django.test.client import Client
@@ -27,6 +27,31 @@ def to_list(value):
         value = [value]
     return value
 
+real_commit = transaction.commit
+real_rollback = transaction.rollback
+real_enter_transaction_management = transaction.enter_transaction_management
+real_leave_transaction_management = transaction.leave_transaction_management
+real_savepoint_commit = transaction.savepoint_commit
+real_savepoint_rollback = transaction.savepoint_rollback
+
+def nop(x=None):
+    return
+
+def disable_transaction_methods():
+    transaction.commit = nop
+    transaction.rollback = nop
+    transaction.savepoint_commit = nop
+    transaction.savepoint_rollback = nop
+    transaction.enter_transaction_management = nop
+    transaction.leave_transaction_management = nop        
+
+def restore_transaction_methods():
+    transaction.commit = real_commit
+    transaction.rollback = real_rollback
+    transaction.savepoint_commit = real_savepoint_commit
+    transaction.savepoint_rollback = real_savepoint_rollback
+    transaction.enter_transaction_management = real_enter_transaction_management
+    transaction.leave_transaction_management = real_leave_transaction_management
 
 class OutputChecker(doctest.OutputChecker):
     def check_output(self, want, got, optionflags):
@@ -173,8 +198,8 @@ class DocTestRunner(doctest.DocTestRunner):
         # Rollback, in case of database errors. Otherwise they'd have
         # side effects on other tests.
         transaction.rollback_unless_managed()
-
-class TestCase(unittest.TestCase):
+        
+class TransactionTestCase(unittest.TestCase):
     def _pre_setup(self):
         """Performs any pre-test setup. This includes:
 
@@ -185,16 +210,22 @@ class TestCase(unittest.TestCase):
               ROOT_URLCONF with it.
             * Clearing the mail test outbox.
         """
+        self._fixture_setup()
+        self._urlconf_setup()
+        mail.outbox = []
+
+    def _fixture_setup(self):
         call_command('flush', verbosity=0, interactive=False)
         if hasattr(self, 'fixtures'):
             # We have to use this slightly awkward syntax due to the fact
             # that we're using *args and **kwargs together.
             call_command('loaddata', *self.fixtures, **{'verbosity': 0})
+
+    def _urlconf_setup(self):
         if hasattr(self, 'urls'):
             self._old_root_urlconf = settings.ROOT_URLCONF
             settings.ROOT_URLCONF = self.urls
             clear_url_caches()
-        mail.outbox = []
 
     def __call__(self, result=None):
         """
@@ -211,7 +242,7 @@ class TestCase(unittest.TestCase):
             import sys
             result.addError(self, sys.exc_info())
             return
-        super(TestCase, self).__call__(result)
+        super(TransactionTestCase, self).__call__(result)        
         try:
             self._post_teardown()
         except (KeyboardInterrupt, SystemExit):
@@ -226,6 +257,13 @@ class TestCase(unittest.TestCase):
 
             * Putting back the original ROOT_URLCONF if it was changed.
         """
+        self._fixture_teardown()
+        self._urlconf_teardown()
+
+    def _fixture_teardown(self):
+        pass
+
+    def _urlconf_teardown(self):        
         if hasattr(self, '_old_root_urlconf'):
             settings.ROOT_URLCONF = self._old_root_urlconf
             clear_url_caches()
@@ -359,3 +397,37 @@ class TestCase(unittest.TestCase):
         self.failIf(template_name in template_names,
             (u"Template '%s' was used unexpectedly in rendering the"
              u" response") % template_name)
+
+class TestCase(TransactionTestCase):
+    """
+    Does basically the same as TransactionTestCase, but surrounds every test
+    with a transaction, monkey-patches the real transaction management routines to 
+    do nothing, and rollsback the test transaction at the end of the test. You have 
+    to use TransactionTestCase, if you need transaction management inside a test.
+    """
+
+    def _fixture_setup(self):
+        if not settings.DATABASE_SUPPORTS_TRANSACTIONS:
+            return super(TestCase, self)._fixture_setup()
+        
+        transaction.enter_transaction_management()
+        transaction.managed(True)
+        disable_transaction_methods()
+
+        from django.contrib.sites.models import Site
+        Site.objects.clear_cache()
+
+        if hasattr(self, 'fixtures'):
+            call_command('loaddata', *self.fixtures, **{
+                                                        'verbosity': 0,
+                                                        'commit': False
+                                                        })
+
+    def _fixture_teardown(self):
+        if not settings.DATABASE_SUPPORTS_TRANSACTIONS:
+            return super(TestCase, self)._fixture_teardown()
+                
+        restore_transaction_methods()
+        transaction.rollback()
+        transaction.leave_transaction_management()
+        connection.close()