Add pytest fixture for testing migrations (TS-2289)

django/conftest.py

@@ -12,6 +12,8 @@
 from django.contrib.sites.models import Site
 from django.core.cache import cache
 from django.core.files.base import File
+from django.db import connection
+from django.db.migrations.executor import MigrationExecutor
 from PIL import Image
 from rest_framework.test import APIClient
 
@@ -110,6 +112,16 @@ def prime_testing_database(django_db_setup, django_db_blocker):
         [x.delete() for x in Site.objects.all()]
 
 
+@pytest.fixture
+def migrate_db_state():
+    def _run_migration(app_name: str, migration: str):
+        executor = MigrationExecutor(connection)
+        executor.migrate([(app_name, migration)])
+        executor.loader.build_graph()
+
+    return _run_migration
+
+
 @pytest.fixture()
 def user(django_user_model):
     return django_user_model.objects.create_user(

django/thunderstore/core/tests/test_migrations.py

@@ -0,0 +1,23 @@
+import pytest
+
+from conftest import migrate_db_state
+from thunderstore.repository.factories import NamespaceFactory, TeamFactory
+from thunderstore.repository.models import Namespace
+
+
+@pytest.mark.django_db
+def test_0055_delete_namespaces_without_team(migrate_db_state):
+    migrate_db_state("repository", "0054_alter_chunked_package_cache_index")
+
+    team = TeamFactory.create()
+    namespace_with_team = NamespaceFactory.create(team=team)
+    namespace_without_team = NamespaceFactory.create(team=None)
+
+    assert namespace_without_team.team is None
+    assert Namespace.objects.count() == 2
+
+    migrate_db_state("repository", "0055_delete_namespaces_without_team")
+
+    assert Namespace.objects.count() == 1
+    assert namespace_with_team in Namespace.objects.all()
+    assert namespace_without_team not in Namespace.objects.all()