diff --git a/tests/middleware/test_session.py b/tests/middleware/test_session.py
index dc1094117..4fbeec88c 100644
--- a/tests/middleware/test_session.py
+++ b/tests/middleware/test_session.py
@@ -1,29 +1,33 @@
 import re
+from typing import Callable
 
 from starlette.applications import Starlette
 from starlette.middleware import Middleware
 from starlette.middleware.sessions import SessionMiddleware
+from starlette.requests import Request
 from starlette.responses import JSONResponse
 from starlette.routing import Mount, Route
 from starlette.testclient import TestClient
 
+TestClientFactory = Callable[..., TestClient]
 
-def view_session(request):
+
+def view_session(request: Request) -> JSONResponse:
     return JSONResponse({"session": request.session})
 
 
-async def update_session(request):
+async def update_session(request: Request) -> JSONResponse:
     data = await request.json()
     request.session.update(data)
     return JSONResponse({"session": request.session})
 
 
-async def clear_session(request):
+async def clear_session(request: Request) -> JSONResponse:
     request.session.clear()
     return JSONResponse({"session": request.session})
 
 
-def test_session(test_client_factory):
+def test_session(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),
@@ -56,7 +60,7 @@ def test_session(test_client_factory):
     assert response.json() == {"session": {}}
 
 
-def test_session_expires(test_client_factory):
+def test_session_expires(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),
@@ -80,7 +84,7 @@ def test_session_expires(test_client_factory):
     assert response.json() == {"session": {}}
 
 
-def test_secure_session(test_client_factory):
+def test_secure_session(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),
@@ -119,7 +123,7 @@ def test_secure_session(test_client_factory):
     assert response.json() == {"session": {}}
 
 
-def test_session_cookie_subpath(test_client_factory):
+def test_session_cookie_subpath(test_client_factory: TestClientFactory) -> None:
     second_app = Starlette(
         routes=[
             Route("/update_session", endpoint=update_session, methods=["POST"]),
@@ -139,7 +143,7 @@ def test_session_cookie_subpath(test_client_factory):
     assert cookie_path == "/second_app"
 
 
-def test_invalid_session_cookie(test_client_factory):
+def test_invalid_session_cookie(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),
@@ -158,7 +162,7 @@ def test_invalid_session_cookie(test_client_factory):
     assert response.json() == {"session": {}}
 
 
-def test_session_cookie(test_client_factory):
+def test_session_cookie(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),
@@ -180,7 +184,7 @@ def test_session_cookie(test_client_factory):
     assert response.json() == {"session": {}}
 
 
-def test_domain_cookie(test_client_factory):
+def test_domain_cookie(test_client_factory: TestClientFactory) -> None:
     app = Starlette(
         routes=[
             Route("/view_session", endpoint=view_session),