Fix south integration with --create-db

This requires to monkey-patch `south.hacks.django_1_0.SkipFlushCommand`,
which has a bug that prevents any initial data to be installed.

South issue: http://south.aeracode.org/ticket/1395#comment:3

Fixes #22

Django code reference for 1.6, from
django-1.6.x/django/db/backends/creation.py(339)create_test_db():

    # Report syncdb messages at one level lower than that requested.
    # This ensures we don't get flooded with messages during testing
    # (unless you really ask to be flooded)
    call_command('syncdb',
        verbosity=max(verbosity - 1, 0),
        interactive=False,
        database=self.connection.alias,
        load_initial_data=False)

    # We need to then do a flush to ensure that any data installed by
    # custom SQL has been removed. The only test data should come from
    # test fixtures, or autogenerated from post_syncdb triggers.
    # This has the side effect of loading initial data (which was
    # intentionally skipped in the syncdb).
    call_command('flush',
        verbosity=max(verbosity - 1, 0),
        interactive=False,
        database=self.connection.alias)

Author: blueyed

docs/changelog.rst

@@ -9,6 +9,9 @@ NEXT
 * Fix admin client with custom user models (#124). Big thanks to Benjamin
   Hedrich and Dmitry Dygalo for patch and tests.
 
+* Fix usage of South migrations, which were unconditionally disabled previously
+  (#22).
+
 2.6.2
 -----
 

docs/faq.rst

@@ -54,8 +54,14 @@ This snippet should do the trick (replace ``yourproject.settings`` and make sure
     echo "export DJANGO_SETTINGS_MODULE=yourproject.settings" >> $VIRTUAL_ENV/bin/postactivate
 
 
-How does South and pytest-django play together?
-Djangos own syncdb will always be used to create the test database, regardless of wheter South is present or not.
+How do South and pytest-django play together?
+---------------------------------------------
+
+pytest-django detects South and applies its monkey-patch, which gets fixed
+to handle initial data properly (which South would skip otherwise, because
+of a bug).
+
+
 Does this work with the pytest-xdist plugin?
 --------------------------------------------
 

generate_configurations.py

@@ -65,6 +65,7 @@ def requirements(env):
     yield 'pytest-xdist==1.10'
     yield DJANGO_REQUIREMENTS[env.django_version]
     yield 'django-configurations==0.8'
+    yield 'south==1.0'
 
     if env.settings == 'postgres':
         # Django 1.3 does not work with recent psycopg2 versions

pytest_django/fixtures.py

@@ -37,6 +37,8 @@ def _django_db_setup(request,
 
     monkey_patch_creation_for_db_suffix(db_suffix)
 
+    _handle_south()
+
     with _django_cursor_wrapper:
         # Monkey patch Django's setup code to support database re-use
         if request.config.getvalue('reuse_db'):
@@ -87,6 +89,40 @@ def flushdb():
         request.addfinalizer(_django_cursor_wrapper.disable)
         request.addfinalizer(case._post_teardown)
 
+def _handle_south():
+    from django.conf import settings
+    if 'south' in settings.INSTALLED_APPS:
+        # Handle south.
+        from django.core import management
+
+        try:
+            # if `south` >= 0.7.1 we can use the test helper
+            from south.management.commands import patch_for_test_db_setup
+        except ImportError:
+            # if `south` < 0.7.1 make sure it's migrations are disabled
+            management.get_commands()
+            management._commands['syncdb'] = 'django.core'
+        else:
+            # Monkey-patch south.hacks.django_1_0.SkipFlushCommand to load
+            # initial data.
+            # Ref: http://south.aeracode.org/ticket/1395#comment:3
+            import south.hacks.django_1_0
+            from django.core.management.commands.flush import Command as FlushCommand
+            class SkipFlushCommand(FlushCommand):
+                def handle_noargs(self, **options):
+                    # Reinstall the initial_data fixture.
+                    from django.core.management import call_command
+                    # `load_initial_data` got introduces with Django 1.5.
+                    load_initial_data = options.get('load_initial_data', None)
+                    if load_initial_data or load_initial_data is None:
+                        # Reinstall the initial_data fixture.
+                        call_command('loaddata', 'initial_data', **options)
+                    # no-op to avoid calling flush
+                    return
+            south.hacks.django_1_0.SkipFlushCommand = SkipFlushCommand
+
+            patch_for_test_db_setup()
+
 ################ User visible fixtures ################
 
 

requirements.txt

@@ -5,3 +5,4 @@ pytest-xdist
 tox
 wheel
 twine
+south

tests/conftest.py

@@ -22,7 +22,7 @@
 @pytest.fixture(scope='function')
 def django_testdir(request, testdir, monkeypatch):
     if get_db_engine() in ('mysql', 'postgresql_psycopg2', 'sqlite3'):
-        # Django requires the production database to exists..
+        # Django requires the production database to exist.
         create_empty_production_database()
 
     if hasattr(request.node.cls, 'db_settings'):
@@ -75,3 +75,16 @@ def create_app_file(code, filename):
     testdir.create_app_file = create_app_file
 
     return testdir
+
+
+@pytest.fixture
+def django_testdir_initial(django_testdir):
+    """A django_testdir fixture which provides initial_data."""
+    django_testdir.makefile('.json', initial_data="""
+        [{
+            "pk": 1,
+            "model": "app.item",
+            "fields": { "name": "mark_initial_data" }
+        }]""")
+
+    return django_testdir

tests/test_db_setup.py

@@ -1,7 +1,10 @@
 import sys
+from textwrap import dedent
 
 import pytest
 
+from pytest_django.lazy_django import get_django_version
+
 from .db_helpers import (db_exists, drop_database, mark_database, mark_exists,
                          skip_if_sqlite_in_memory)
 
@@ -191,3 +194,109 @@ def test_a():
 
         result = django_testdir.runpytest('--tb=short', '-vv', '-n1')
         result.stdout.fnmatch_lines(['*PASSED*test_a*'])
+
+
+def test_initial_data(django_testdir_initial):
+    """Test that initial data gets loaded."""
+    django_testdir_initial.create_test_module('''
+        import pytest
+
+        from .app.models import Item
+
+        @pytest.mark.django_db
+        def test_inner_south():
+            assert [x.name for x in Item.objects.all()] \
+                == ["mark_initial_data"]
+    ''')
+
+    result = django_testdir_initial.runpytest('--tb=short', '-v')
+    result.stdout.fnmatch_lines(['*test_inner_south*PASSED*'])
+
+
+# NOTE: South tries to monkey-patch management._commands, which has been
+#       replaced by lru_cache and would cause an AttributeError.
+@pytest.mark.skipif(get_django_version() >= (1, 7),
+                    reason='South fails with Django 1.7.')
+@pytest.mark.skipif(sys.version_info[:2] == (3, 4),
+                    reason='South fails on Python 3.4.')
+class TestSouth:
+    """Test interaction with initial_data and South."""
+
+    @pytest.mark.extra_settings(dedent("""
+        INSTALLED_APPS += [ 'south', ]
+        SOUTH_TESTS_MIGRATE = True
+        SOUTH_MIGRATION_MODULES = {
+            'app': 'app.south_migrations',
+        }
+        """))
+    def test_initial_data_south(self, django_testdir_initial, settings):
+        django_testdir_initial.create_test_module('''
+            import pytest
+
+            from .app.models import Item
+
+            @pytest.mark.django_db
+            def test_inner_south():
+                assert [x.name for x in Item.objects.all()] \
+                    == ["mark_initial_data"]
+        ''')
+
+        result = django_testdir_initial.runpytest('--tb=short', '-v')
+        result.stdout.fnmatch_lines(['*test_inner_south*PASSED*'])
+
+    @pytest.mark.extra_settings(dedent("""
+        INSTALLED_APPS += [ 'south', ]
+        SOUTH_TESTS_MIGRATE = True
+        SOUTH_MIGRATION_MODULES = {
+            'app': 'tpkg.app.south_migrations',
+        }
+        """))
+    def test_initial_south_migrations(self, django_testdir_initial, settings):
+        testdir = django_testdir_initial
+        testdir.create_test_module('''
+            import pytest
+
+            @pytest.mark.django_db
+            def test_inner_south():
+                pass
+            ''')
+
+        testdir.mkpydir('tpkg/app/south_migrations')
+        p = testdir.tmpdir.join(
+            "tpkg/app/south_migrations/0001_initial").new(ext="py")
+        p.write(dedent("""
+            from south.v2 import SchemaMigration
+
+            class Migration(SchemaMigration):
+                def forwards(self, orm):
+                    print("mark_south_migration_forwards")
+            """), ensure=True)
+
+        result = testdir.runpytest('--tb=short', '-v', '-s')
+        result.stdout.fnmatch_lines(['*mark_south_migration_forwards*'])
+
+    @pytest.mark.extra_settings(dedent("""
+        INSTALLED_APPS += [ 'south', ]
+        SOUTH_TESTS_MIGRATE = False
+        SOUTH_MIGRATION_MODULES = {
+            'app': 'tpkg.app.south_migrations',
+        }
+        """))
+    def test_south_no_migrations(self, django_testdir_initial, settings):
+        testdir = django_testdir_initial
+        testdir.create_test_module('''
+            import pytest
+
+            @pytest.mark.django_db
+            def test_inner_south():
+                pass
+        ''')
+
+        testdir.mkpydir('tpkg/app/south_migrations')
+        p = testdir.tmpdir.join(
+            "tpkg/app/south_migrations/0001_initial").new(ext="py")
+        p.write('raise Exception("This should not get imported.")',
+                ensure=True)
+
+        result = testdir.runpytest('--tb=short', '-v')
+        result.stdout.fnmatch_lines(['*test_inner_south*PASSED*'])