Fixed #35402 -- Fixed crash when DatabaseFeatures.django_test_skips r…

…eferences a class in another test module

Previously, if a submodule skipped test classes in an adjacent submodule (same
parent module), only the running submodule was imported and an error was thrown
because getattr would not find the submodule of the to-be-skipped class. Updated
cached_import in django/utils/module_loading.py to include a check for the skipped
submodule, and import it if it is not there.

Thanks to Tim Graham for reporting this bug

django/db/backends/base/creation.py

@@ -347,19 +347,12 @@ def mark_expected_failures_and_skips(self):
         for reason, tests in self.connection.features.django_test_skips.items():
             for test_name in tests:
                 test_case_name, _, test_method_name = test_name.rpartition(".")
-                if not test_method_name.startswith("test"):
-                    test_case_name = test_name
-                    test_method_name = None
                 test_app = test_name.split(".")[0]
                 # Importing a test app that isn't installed raises RuntimeError.
                 if test_app in settings.INSTALLED_APPS:
                     test_case = import_string(test_case_name)
-                    if test_method_name:
-                        test_method = getattr(test_case, test_method_name)
-                        setattr(test_case, test_method_name, skip(reason)(test_method))
-                    else:
-                        setattr(test_case, "__unittest_skip__", True)
-                        setattr(test_case, "__unittest_skip_why__", reason)
+                    test_method = getattr(test_case, test_method_name)
+                    setattr(test_case, test_method_name, skip(reason)(test_method))
 
     def sql_table_creation_suffix(self):
         """

django/utils/module_loading.py

@@ -13,6 +13,8 @@ def cached_import(module_path, class_name):
         and getattr(spec, "_initializing", False) is False
     ):
         module = import_module(module_path)
+    if not hasattr(module, class_name):
+        import_module(f"{module_path}.{class_name}")
     return getattr(module, class_name)
 
 

tests/backends/base/test_creation.py

@@ -292,6 +292,9 @@ def test_mark_expected_failures_and_skips(self):
             "skip test class": {
                 "backends.base.test_creation.SkipTestClass",
             },
+            "skip another submodule test class": {
+                "backends.base.test_features.TestDatabaseFeatures",
+            },
             "skip test function": {
                 "backends.base.test_creation.test_skip_test_function",
             },