Improve test ordering with Django test classes (#830)

Author: pmourlanne

pytest_django/plugin.py

@@ -417,7 +417,20 @@ def pytest_runtest_setup(item):
 
 @pytest.hookimpl(tryfirst=True)
 def pytest_collection_modifyitems(items):
+    # If Django is not configured we don't need to bother
+    if not django_settings_is_configured():
+        return
+
+    from django.test import TestCase, TransactionTestCase
+
     def get_order_number(test):
+        if hasattr(test, "cls") and test.cls:
+            # Beware, TestCase is a subclass of TransactionTestCase
+            if issubclass(test.cls, TestCase):
+                return 0
+            if issubclass(test.cls, TransactionTestCase):
+                return 1
+
         marker_db = test.get_closest_marker('django_db')
         if marker_db:
             transaction = validate_django_db(marker_db)[0]

tests/test_db_setup.py

@@ -33,7 +33,9 @@ def test_db_order(django_testdir):
     """Test order in which tests are being executed."""
 
     django_testdir.create_test_module('''
+        from unittest import TestCase
         import pytest
+        from django.test import SimpleTestCase, TestCase as DjangoTestCase, TransactionTestCase
 
         from .app.models import Item
 
@@ -50,14 +52,34 @@ def test_run_first_fixture(db):
         @pytest.mark.django_db
         def test_run_first_decorator():
             pass
+
+        class MyTestCase(TestCase):
+            def test_run_last_test_case(self):
+                pass
+
+        class MySimpleTestCase(SimpleTestCase):
+            def test_run_last_simple_test_case(self):
+                pass
+
+        class MyDjangoTestCase(DjangoTestCase):
+            def test_run_first_django_test_case(self):
+                pass
+
+        class MyTransactionTestCase(TransactionTestCase):
+            def test_run_second_transaction_test_case(self):
+                pass
     ''')
     result = django_testdir.runpytest_subprocess('-v', '-s')
     assert result.ret == 0
     result.stdout.fnmatch_lines([
         "*test_run_first_fixture*",
         "*test_run_first_decorator*",
+        "*test_run_first_django_test_case*",
         "*test_run_second_decorator*",
         "*test_run_second_fixture*",
+        "*test_run_second_transaction_test_case*",
+        "*test_run_last_test_case*",
+        "*test_run_last_simple_test_case*",
     ])