fix(review): address PR feedback - type narrowing, full URL assertion, parametrized test

- Replace type: ignore[union-attr] with proper cast() type narrowing
- Assert full URL instead of substring match in deployment test
- Add parametrized test for /chat/completions endpoint
- Move import json to module scope for consistency

Refs: openai#2910

Author: giulio-leone

src/openai/lib/azure.py

@@ -61,10 +61,11 @@ def _build_request(
         retries_taken: int = 0,
     ) -> httpx.Request:
         if options.url in _deployments_endpoints and is_mapping(options.json_data):
-            model = options.json_data.get("model")
+            json_data = cast(Mapping[str, Any], options.json_data)
+            model = json_data.get("model")
             if model is not None and "/deployments" not in str(self.base_url.path):
                 options.url = f"/deployments/{model}{options.url}"
-                options.json_data = {k: v for k, v in options.json_data.items() if k != "model"}  # type: ignore[union-attr]
+                options.json_data = {k: v for k, v in json_data.items() if k != "model"}
 
         return super()._build_request(options, retries_taken=retries_taken)
 

tests/lib/test_azure.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import json
 import logging
 from typing import Union, cast
 from typing_extensions import Literal, Protocol
@@ -56,12 +57,32 @@ def test_implicit_deployment_strips_model_from_body(client: Client) -> None:
             json_data={"model": "gpt-image-1-5", "prompt": "sunset"},
         )
     )
-    import json
 
     body = json.loads(req.content.decode())
     assert "model" not in body
     assert body["prompt"] == "sunset"
-    assert "/deployments/gpt-image-1-5/" in str(req.url)
+    assert (
+        str(req.url)
+        == "https://example-resource.azure.openai.com/openai/deployments/gpt-image-1-5/images/generations?api-version=2023-07-01"
+    )
+
+
+@pytest.mark.parametrize("client", [sync_client, async_client])
+def test_implicit_deployment_strips_model_from_body_chat(client: Client) -> None:
+    req = client._build_request(
+        FinalRequestOptions.construct(
+            method="post",
+            url="/chat/completions",
+            json_data={"model": "gpt-4o", "messages": [{"role": "user", "content": "hi"}]},
+        )
+    )
+    body = json.loads(req.content.decode())
+    assert "model" not in body
+    assert body["messages"] == [{"role": "user", "content": "hi"}]
+    assert (
+        str(req.url)
+        == "https://example-resource.azure.openai.com/openai/deployments/gpt-4o/chat/completions?api-version=2023-07-01"
+    )
 
 
 @pytest.mark.parametrize(