Migrate apps/test_config.yml 'assert_type' tests (#2190)

* Migrate `apps/test_config.yml` 'assert_type' tests

* fixup! Migrate `apps/test_config.yml` 'assert_type' tests

Author: flaeppe

tests/assert_type/apps/test_config.py

@@ -0,0 +1,38 @@
+from django.apps.config import AppConfig
+from django.utils.functional import cached_property
+from typing_extensions import assert_type
+
+
+class FooConfig(AppConfig):
+    name = "foo"
+    default_auto_field = "django.db.models.BigAutoField"
+
+
+class BarConfig(AppConfig):
+    name = "foo"
+
+    @property
+    def default_auto_field(self) -> str:  # type: ignore[override]
+        return "django.db.models.BigAutoField"
+
+
+class BazConfig(AppConfig):
+    name = "foo"
+
+    @cached_property
+    def default_auto_field(self) -> str:  # type: ignore[override]
+        return "django.db.models.BigAutoField"
+
+
+class FooBarConfig(AppConfig):
+    name = "foo"
+    default_auto_field = cached_property(lambda self: "django.db.models.BigAutoField")
+
+
+# Pyright correctly picks up our fake '_Getter' descriptor on class level. But we
+# silence the pyright error since mypy doesn't follow along and the fake descriptor
+# is a stubs detail made to round other problems.
+assert_type(FooConfig.default_auto_field, str)  # pyright: ignore[reportAssertTypeFailure]
+assert_type(BarConfig("bar", None).default_auto_field, str)
+assert_type(BazConfig("baz", None).default_auto_field, str)
+assert_type(FooBarConfig("baz", None).default_auto_field, str)