test(6838): give the test request its socket peer the way Quart reads it

Quart takes remote_addr from a Remote-Addr header its ASGI layer writes from
the scope (replacing any the client sent). A test request context does not
read scope_base for it, so the two socket-peer tests saw an empty address.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_proxy.py

@@ -50,9 +50,10 @@ def _app() -> Quart:
 
 
 def _context(app, headers=None, scheme="http"):
+    # Quart's ASGI layer writes the socket peer into a Remote-Addr header,
+    # replacing any the client sent; a test request context takes it as given.
     return app.test_request_context(
-        "/", headers=headers or {}, scheme=scheme,
-        scope_base={"client": (PEER, 40000)},
+        "/", headers={"Remote-Addr": PEER, **(headers or {})}, scheme=scheme,
     )
 
 
@@ -76,10 +77,8 @@ async def test_no_header_reads_the_socket_peer(monkeypatch):
 
 async def test_a_header_sent_twice_is_read_as_one_chain(monkeypatch):
     monkeypatch.setattr(Config, "TRUSTED_PROXY_HOPS", 1)
-    headers = [("X-Forwarded-For", FORGED), ("X-Forwarded-For", CLIENT)]
-    async with _app().test_request_context(
-        "/", headers=headers, scope_base={"client": (PEER, 40000)},
-    ):
+    headers = [("Remote-Addr", PEER), ("X-Forwarded-For", FORGED), ("X-Forwarded-For", CLIENT)]
+    async with _app().test_request_context("/", headers=headers):
         assert client_ip() == CLIENT