Use Django's --keepdb with Django 1.8+

Django 1.8 supports `--keepdb` [1], and it makes sense to make use of
it.  This should probably handle migrations in the context of
`transactional_db` better, i.e. by re-applying migrations with a flushed
DB.

1: https://docs.djangoproject.com/en/1.8/ref/django-admin/#django-admin-option---keepdb

Author: blueyed

pytest_django/db_reuse.py

@@ -95,6 +95,8 @@ def create_test_db_with_reuse(self, verbosity=1, autoclobber=False,
     This method is a monkey patched version of create_test_db that
     will not actually create a new database, but just reuse the
     existing.
+
+    This is only used with Django < 1.8.
     """
     test_database_name = self._get_test_db_name()
     self.connection.settings_dict['NAME'] = test_database_name

pytest_django/fixtures.py

@@ -43,15 +43,18 @@ def _django_db_setup(request,
     if request.config.getvalue('nomigrations'):
         _disable_native_migrations()
 
+    db_args = {}
     with _django_cursor_wrapper:
-        # Monkey patch Django's setup code to support database re-use
-        if request.config.getvalue('reuse_db'):
-            if not request.config.getvalue('create_db'):
+        if (request.config.getvalue('reuse_db') and
+                not request.config.getvalue('create_db')):
+            if get_django_version() >= (1, 8):
+                db_args['keepdb'] = True
+            else:
                 monkey_patch_creation_for_db_reuse()
 
         # Create the database
         db_cfg = setup_databases(verbosity=pytest.config.option.verbose,
-                                 interactive=False)
+                                 interactive=False, **db_args)
 
     def teardown_database():
         with _django_cursor_wrapper:

tests/test_environment.py

@@ -188,8 +188,8 @@ def test_more_verbose_with_vv(self, testdir):
             "*PASSED*Destroying test database for alias 'default' ('*')...*"])
 
     def test_more_verbose_with_vv_and_reusedb(self, testdir):
-        """More verbose output with '-v -v', and --reuse-db."""
-        result = testdir.runpytest_subprocess('-s', '-v', '-v', '--reuse-db')
+        """More verbose output with '-v -v', and --create-db."""
+        result = testdir.runpytest_subprocess('-s', '-v', '-v', '--create-db')
         result.stdout.fnmatch_lines([
             "tpkg/test_the_test.py:*Creating test database for alias*",
             "*PASSED*"])