Add Generic for TestClient.app

CHANGES/8977.bugfix.rst

@@ -0,0 +1 @@
+Made ``TestClient.app`` a ``Generic`` so type checkers will know the correct type (avoid unneeded ``client.app is not None`` checks) -- by :user:`Dreamsorcerer`.

aiohttp/pytest_plugin.py

@@ -48,15 +48,15 @@
         *,
         server_kwargs: Optional[Dict[str, Any]] = None,
         **kwargs: Any
-    ) -> TestClient[Request]: ...
+    ) -> TestClient[Request, Application]: ...
     @overload
     async def __call__(
         self,
         __param: BaseTestServer[_Request],
         *,
         server_kwargs: Optional[Dict[str, Any]] = None,
         **kwargs: Any
-    ) -> TestClient[_Request]: ...
+    ) -> TestClient[_Request, None]: ...
 
 
 class AiohttpServer(Protocol):
@@ -335,7 +335,7 @@
 
 
 @pytest.fixture
-def aiohttp_client_cls() -> Type[TestClient[Any]]:
+def aiohttp_client_cls() -> Type[TestClient[Any, Any]]:
     """
     Client class to use in ``aiohttp_client`` factory.
 
@@ -363,7 +363,7 @@
 
 @pytest.fixture
 def aiohttp_client(
-    loop: asyncio.AbstractEventLoop, aiohttp_client_cls: Type[TestClient[Any]]
+    loop: asyncio.AbstractEventLoop, aiohttp_client_cls: Type[TestClient[Any, Any]]
 ) -> Iterator[AiohttpClient]:
     """Factory to create a TestClient instance.
 
@@ -379,20 +379,20 @@
         *,
         server_kwargs: Optional[Dict[str, Any]] = None,
         **kwargs: Any
-    ) -> TestClient[Request]: ...
+    ) -> TestClient[Request, Application]: ...
     @overload
     async def go(
         __param: BaseTestServer[_Request],
         *,
         server_kwargs: Optional[Dict[str, Any]] = None,
         **kwargs: Any
-    ) -> TestClient[_Request]: ...
+    ) -> TestClient[_Request, None]: ...
     async def go(
         __param: Union[Application, BaseTestServer[Any]],
         *,
         server_kwargs: Optional[Dict[str, Any]] = None,
         **kwargs: Any
-    ) -> TestClient[Any]:
+    ) -> TestClient[Any, Any]:
         if isinstance(__param, Application):
             server_kwargs = server_kwargs or {}
             server = TestServer(__param, **server_kwargs)

aiohttp/test_utils.py

@@ -22,6 +22,7 @@
     TypeVar,
     Union,
     cast,
+    overload,
 )
 from unittest import IsolatedAsyncioTestCase, mock
 
@@ -70,6 +71,7 @@
 else:
     Self = Any
 
+_ApplicationNone = TypeVar("_ApplicationNone", Application, None)
 _Request = TypeVar("_Request", bound=BaseRequest)
 
 REUSE_ADDRESS = os.name == "posix" and sys.platform != "cygwin"
@@ -251,7 +253,7 @@
         return ServerRunner(srv, **kwargs)
 
 
-class TestClient(Generic[_Request]):
+class TestClient(Generic[_Request, _ApplicationNone]):
     """
     A test client implementation.
 
@@ -261,7 +263,23 @@
 
     __test__ = False
 
+    @overload
     def __init__(
+        self: TestClient[Request, Application],
+        server: TestServer,
+        *,
+        cookie_jar: Optional[AbstractCookieJar] = None,
+        **kwargs: Any,
+    ) -> None: ...
+    @overload
+    def __init__(
+        self: TestClient[_Request, None],
+        server: BaseTestServer[_Request],
+        *,
+        cookie_jar: Optional[AbstractCookieJar] = None,
+        **kwargs: Any,
+    ) -> None: ...
+    def __init__(  # type: ignore[misc]
         self,
         server: BaseTestServer[_Request],
         *,
@@ -300,8 +318,8 @@
         return self._server
 
     @property
-    def app(self) -> Optional[Application]:
-        return cast(Optional[Application], getattr(self._server, "app", None))
+    def app(self) -> _ApplicationNone:
+        return getattr(self._server, "app", None)  # type: ignore[return-value]
 
     @property
     def session(self) -> ClientSession:
@@ -505,7 +523,7 @@
         """Return a TestServer instance."""
         return TestServer(app)
 
-    async def get_client(self, server: TestServer) -> TestClient[Request]:
+    async def get_client(self, server: TestServer) -> TestClient[Request, Application]:
         """Return a TestClient instance."""
         return TestClient(server)
 

tests/test_client_functional.py

@@ -3716,7 +3716,7 @@ async def handler(request: web.Request) -> web.Response:
             await resp.write(b"1" * 1000)
             await asyncio.sleep(0.01)
 
-    async def request(client: TestClient[web.Request]) -> None:
+    async def request(client: TestClient[web.Request, web.Application]) -> None:
         timeout = aiohttp.ClientTimeout(total=0.5)
         async with await client.get("/", timeout=timeout) as resp:
             with pytest.raises(asyncio.TimeoutError):

tests/test_test_utils.py

@@ -1,6 +1,7 @@
 import asyncio
 import gzip
 import socket
+import sys
 from typing import Callable, Iterator, List, Mapping, NoReturn
 from unittest import mock
 
@@ -20,7 +21,10 @@
     make_mocked_request,
 )
 
-_TestClient = TestClient[web.Request]
+if sys.version_info >= (3, 11):
+    from typing import assert_type
+
+_TestClient = TestClient[web.Request, web.Application]
 
 _hello_world_str = "Hello, world"
 _hello_world_bytes = _hello_world_str.encode("utf-8")
@@ -71,7 +75,7 @@ def app() -> web.Application:
 def test_client(
     loop: asyncio.AbstractEventLoop, app: web.Application
 ) -> Iterator[_TestClient]:
-    async def make_client() -> TestClient[web.Request]:
+    async def make_client() -> TestClient[web.Request, web.Application]:
         return TestClient(TestServer(app))
 
     client = loop.run_until_complete(make_client())
@@ -239,6 +243,8 @@ async def test_test_client_props() -> None:
     async with client:
         assert isinstance(client.port, int)
         assert client.server is not None
+        if sys.version_info >= (3, 11):
+            assert_type(client.app, web.Application)
         assert client.app is not None
     assert client.port is None
 
@@ -255,6 +261,8 @@ async def hello(request: web.BaseRequest) -> NoReturn:
     async with client:
         assert isinstance(client.port, int)
         assert client.server is not None
+        if sys.version_info >= (3, 11):
+            assert_type(client.app, None)
         assert client.app is None
     assert client.port is None
 
@@ -271,7 +279,7 @@ async def test_test_server_context_manager(loop: asyncio.AbstractEventLoop) -> N
 
 def test_client_unsupported_arg() -> None:
     with pytest.raises(TypeError) as e:
-        TestClient("string")  # type: ignore[arg-type]
+        TestClient("string")  # type: ignore[call-overload]
 
     assert (
         str(e.value) == "server must be TestServer instance, found type: <class 'str'>"