Fixed #28478 -- Make DiscoverRunner skip creating unused test databases.

SimpleTestCase.databases makes it possible to determine the set of
databases required to run the discovered tests.

2 files changed, 18 insertions, 0 deletions

diff --git a/tests/test_runner_apps/databases/__init__.py b/tests/test_runner_apps/databases/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/test_runner_apps/databases/__init__.py
diff --git a/tests/test_runner_apps/databases/tests.py b/tests/test_runner_apps/databases/tests.py
new file mode 100644
index 0000000000..4be260e689
--- /dev/null
+++ b/tests/test_runner_apps/databases/tests.py
@@ -0,0 +1,18 @@
+import unittest
+
+
+class NoDatabaseTests(unittest.TestCase):
+    def test_nothing(self):
+        pass
+
+
+class DefaultDatabaseTests(NoDatabaseTests):
+    databases = {'default'}
+
+
+class OtherDatabaseTests(NoDatabaseTests):
+    databases = {'other'}
+
+
+class AllDatabasesTests(NoDatabaseTests):
+    databases = '__all__'