Also test 3.14-only behavior

src/typeguard/_decorators.py

@@ -117,7 +117,10 @@ def instrument(f: T_CallableOrType) -> FunctionType | str:
     new_function.__module__ = f.__module__
     new_function.__name__ = f.__name__
     new_function.__qualname__ = f.__qualname__
-    new_function.__annotations__ = f.__annotations__
+    if sys.version_info >= (3, 14):
+        new_function.__annotate__ = f.__annotate__
+    else:
+        new_function.__annotations__ = f.__annotations__
     new_function.__doc__ = f.__doc__
     new_function.__defaults__ = f.__defaults__
     new_function.__kwdefaults__ = f.__kwdefaults__

tests/test_instrumentation.py

@@ -35,27 +35,38 @@ def method(request: FixtureRequest) -> str:
     return request.param
 
 
-@pytest.fixture(scope="module")
-def dummymodule(method: str):
+def _fixture_module(name: str, method: str):
     config.debug_instrumentation = True
     sys.path.insert(0, str(this_dir))
     try:
-        sys.modules.pop("dummymodule", None)
+        sys.modules.pop(name, None)
         if cached_module_path.exists():
             cached_module_path.unlink()
 
         if method == "typechecked":
-            return import_module("dummymodule")
+            return import_module(name)
 
-        with install_import_hook(["dummymodule"]):
+        with install_import_hook([name]):
             with warnings.catch_warnings():
                 warnings.filterwarnings("error", module="typeguard")
-                module = import_module("dummymodule")
+                module = import_module(name)
                 return module
     finally:
         sys.path.remove(str(this_dir))
 
 
+@pytest.fixture(scope="module")
+def dummymodule(method: str):
+    return _fixture_module("dummymodule", method)
+
+
+@pytest.fixture(scope="module")
+def deferredannos(method: str):
+    if sys.version_info < (3, 14):
+        raise pytest.skip("Deferred annotations are only supported in Python 3.14+")
+    return _fixture_module("deferredannos", method)
+
+
 def test_type_checked_func(dummymodule):
     assert dummymodule.type_checked_func(2, 3) == 6
 
@@ -342,3 +353,16 @@ def test_suppress_annotated_assignment(dummymodule):
 def test_suppress_annotated_multi_assignment(dummymodule):
     with suppress_type_checks():
         assert dummymodule.multi_assign_single_value() == (6, 6, 6)
+
+
+class TestUsesForwardRef:
+    def test_success(self, deferredannos):
+        obj = deferredannos.NotYetDefined()
+        assert deferredannos.uses_forwardref(obj) is obj
+
+    def test_failure(self, deferredannos):
+        with pytest.raises(
+            TypeCheckError,
+            match=r'argument "x" \(int\) is not an instance of deferredannos.NotYetDefined',
+        ):
+            deferredannos.uses_forwardref(1)