Fixed #25109 -- Stopped silencing explicitly specified migration modules import errors.

Thanks Tim for the review.

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/migrations/test_loader.py b/tests/migrations/test_loader.py
index b8c2cd8142..5b31fcbd2c 100644
--- a/tests/migrations/test_loader.py
+++ b/tests/migrations/test_loader.py
@@ -205,6 +205,22 @@ class LoaderTests(TestCase):
         self.assertEqual(migration_loader.migrated_apps, set())
         self.assertEqual(migration_loader.unmigrated_apps, {'migrated_app'})
 
+    @override_settings(
+        INSTALLED_APPS=['migrations.migrations_test_apps.migrated_app'],
+        MIGRATION_MODULES={'migrated_app': 'missing-module'},
+    )
+    def test_explicit_missing_module(self):
+        """
+        If a MIGRATION_MODULES override points to a missing module, the error
+        raised during the importation attempt should be propagated unless
+        `ignore_no_migrations=True`.
+        """
+        with self.assertRaisesMessage(ImportError, 'missing-module'):
+            migration_loader = MigrationLoader(connection)
+        migration_loader = MigrationLoader(connection, ignore_no_migrations=True)
+        self.assertEqual(migration_loader.migrated_apps, set())
+        self.assertEqual(migration_loader.unmigrated_apps, {'migrated_app'})
+
     @override_settings(MIGRATION_MODULES={"migrations": "migrations.test_migrations_squashed"})
     def test_loading_squashed(self):
         "Tests loading a squashed migration"