fix(review): add integration test for response header redaction in _base_client

Adds a test using respx to verify that sensitive response headers
are actually redacted in log output when making real client calls,
not just testing the filter utility in isolation.

Refs: #2918

Author: giulio-leone

tests/test_utils/test_logging.py

@@ -1,8 +1,11 @@
 import logging
 from typing import Any, Dict, cast
 
+import httpx
 import pytest
+from respx import MockRouter
 
+from openai import OpenAI
 from openai._utils import SensitiveHeadersFilter, redact_sensitive_headers
 
 
@@ -113,3 +116,29 @@ def test_response_headers_redaction() -> None:
     assert filtered["authorization"] == "<redacted>"
     assert filtered["api-key"] == "<redacted>"
     assert filtered["x-request-id"] == "req_abc123"
+
+
+@pytest.mark.respx(base_url="https://api.openai.com/v1")
+def test_response_header_redaction_in_client(
+    respx_mock: MockRouter,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Integration test: verify _base_client.py redacts sensitive response headers in actual log output."""
+    respx_mock.post("/chat/completions").mock(
+        return_value=httpx.Response(
+            200,
+            json={"id": "chatcmpl-test", "object": "chat.completion", "choices": [], "created": 0, "model": "gpt-4"},
+            headers={"authorization": "Bearer secret", "x-request-id": "req_123"},
+        )
+    )
+
+    client = OpenAI(api_key="test-key", base_url="https://api.openai.com/v1")
+
+    with caplog.at_level(logging.DEBUG, logger="openai"):
+        client.chat.completions.create(messages=[], model="gpt-4")
+
+    response_logs = [r for r in caplog.records if r.getMessage().startswith("HTTP Response:")]
+    assert len(response_logs) >= 1, "Expected at least one 'HTTP Response:' log line"
+    msg = response_logs[0].getMessage()
+    assert "secret" not in msg, "Sensitive header value should be redacted in log output"
+    assert "<redacted>" in msg, "Redacted placeholder should appear in log output"