test(prometheus): add regression tests for status_code=None (#24224)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_litellm/integrations/test_prometheus_status_code_none.py

@@ -0,0 +1,41 @@
+"""
+Regression tests for #24224 — status_code=None in Prometheus metrics
+"""
+import pytest
+from prometheus_client import REGISTRY
+
+from litellm.integrations.prometheus import PrometheusLogger
+
+
+@pytest.fixture(scope="function")
+def prometheus_logger():
+    collectors = list(REGISTRY._collector_to_names.keys())
+    for collector in collectors:
+        REGISTRY.unregister(collector)
+    return PrometheusLogger()
+
+
+def test_extract_status_code_returns_int_for_exception_with_status_code(prometheus_logger):
+    """Exception with status_code attribute should return that code."""
+    exc = Exception("fail")
+    exc.status_code = 429  # type: ignore
+    assert prometheus_logger._extract_status_code(exception=exc) == 429
+
+
+def test_extract_status_code_returns_int_for_proxy_exception_with_code(prometheus_logger):
+    """ProxyException-style exception with code attribute should return that code."""
+    exc = Exception("fail")
+    exc.code = 403  # type: ignore
+    assert prometheus_logger._extract_status_code(exception=exc) == 403
+
+
+def test_extract_status_code_defaults_to_500_for_bare_exception(prometheus_logger):
+    """Exception with no status_code or code should default to 500, not None."""
+    exc = Exception("something broke")
+    result = prometheus_logger._extract_status_code(exception=exc)
+    assert result == 500, f"Expected 500 for bare exception, got {result}"
+
+
+def test_extract_status_code_returns_none_when_no_exception(prometheus_logger):
+    """When no exception is provided at all, should return None."""
+    assert prometheus_logger._extract_status_code() is None