Add tests for type hint resolution

rest_framework_dataclasses/typing_utils.py

@@ -56,8 +56,9 @@ def get_resolved_type_hints(tp: type) -> typing.Dict[str, type]:
     Resolving the type hints means converting any stringified type hint into an actual type object. These can come from
     either forward references (PEP 484), or postponed evaluation (PEP 563).
     """
-    # typing.get_type_hints() does the heavy lifting for us, except when using PEP 585 generic types that contain a
-    # stringified type hint (see https://bugs.python.org/issue41370)
+    # typing.get_type_hints() does the heavy lifting for us, except:
+    # - when using PEP 585 generic types that contain a stringified type hint, on Python 3.9 and 3.10. See
+    #   https://bugs.python.org/issue41370
     def _resolve_type(context_type: type, resolve_type: typing.Union[str, type]) -> type:
         if isinstance(resolve_type, str):
             globalsns = sys.modules[context_type.__module__].__dict__

tests/test_typing_utils.py

@@ -11,6 +11,25 @@ def assertAnyTypeEquivalent(self, tp: type):
         # 3.7 and 3.8). It's essentially the same, and we strip the typevar before usage anyway.
         self.assertTrue(tp is typing.Any or (isinstance(tp, typing.TypeVar) and len(tp.__constraints__) == 0))
 
+    def test_resolve(self):
+        class Hinted:
+            a: str
+            b: 'str'
+
+        hints = typing_utils.get_resolved_type_hints(Hinted)
+        self.assertEqual(hints['a'], str)
+        self.assertEqual(hints['b'], str)
+
+    @unittest.skipIf(sys.version_info < (3, 9, 0), 'Python 3.9 required')
+    def test_resolve_pep585(self):
+        class Hinted:
+            a: list[str]
+            b: list['str']
+
+        hints = typing_utils.get_resolved_type_hints(Hinted)
+        self.assertEqual(hints['a'], types_module.GenericAlias(list, (str, )))
+        self.assertEqual(hints['b'], types_module.GenericAlias(list, (str, )))
+
     def test_iterable(self):
         self.assertTrue(typing_utils.is_iterable_type(typing.Iterable[str]))
         self.assertTrue(typing_utils.is_iterable_type(typing.Collection[str]))