From efa03ebd64b9a1927cb6d0da61784b400fa5a0de Mon Sep 17 00:00:00 2001
From: Marcelo Trylesinski <marcelotryle@gmail.com>
Date: Sat, 16 Dec 2023 14:55:20 +0100
Subject: [PATCH] Merge URLs properly on TestClient (#2376)

---
 starlette/testclient.py          |  2 +-
 tests/middleware/test_session.py |  2 +-
 tests/test_testclient.py         | 10 ++++++++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/starlette/testclient.py b/starlette/testclient.py
index 60ef322d1..04ac90a05 100644
--- a/starlette/testclient.py
+++ b/starlette/testclient.py
@@ -463,7 +463,7 @@ def request(  # type: ignore[override]
         ] = httpx._client.USE_CLIENT_DEFAULT,
         extensions: typing.Optional[typing.Dict[str, typing.Any]] = None,
     ) -> httpx.Response:
-        url = self.base_url.join(url)
+        url = self._merge_url(url)
         redirect = self._choose_redirect_arg(follow_redirects, allow_redirects)
         return super().request(
             method,
diff --git a/tests/middleware/test_session.py b/tests/middleware/test_session.py
index 8500f7b54..dc1094117 100644
--- a/tests/middleware/test_session.py
+++ b/tests/middleware/test_session.py
@@ -130,7 +130,7 @@ def test_session_cookie_subpath(test_client_factory):
     )
     app = Starlette(routes=[Mount("/second_app", app=second_app)])
     client = test_client_factory(app, base_url="http://testserver/second_app")
-    response = client.post("/second_app/update_session", json={"some": "data"})
+    response = client.post("/update_session", json={"some": "data"})
     assert response.status_code == 200
     cookie = response.headers["set-cookie"]
     cookie_path_match = re.search(r"; path=(\S+);", cookie)
diff --git a/tests/test_testclient.py b/tests/test_testclient.py
index 03f27e28d..44bcd7ace 100644
--- a/tests/test_testclient.py
+++ b/tests/test_testclient.py
@@ -354,3 +354,13 @@ def homepage(request: Request) -> JSONResponse:
     client = test_client_factory(app)
     response = client.get("/", headers=[("x-token", "foo"), ("x-token", "bar")])
     assert response.json() == {"x-token": ["foo", "bar"]}
+
+
+def test_merge_url(test_client_factory: Callable[..., TestClient]):
+    def homepage(request: Request) -> Response:
+        return Response(request.url.path)
+
+    app = Starlette(routes=[Route("/api/v1/bar", endpoint=homepage)])
+    client = test_client_factory(app, base_url="http://testserver/api/v1/")
+    response = client.get("/bar")
+    assert response.text == "/api/v1/bar"