DX-120403 Make stdlib JSON log test CI-stable

Author: aniket-s-kulkarni

tests/test_log.py

@@ -16,6 +16,7 @@
 
 import os
 import sys
+import io
 import json
 import pytest
 import logging
@@ -166,24 +167,28 @@ def test_configure_with_json_logging(self):
     def test_stdlib_logs_are_rendered_as_json(self, capsys):
         """Stdlib loggers should share the same JSON formatter pipeline."""
         log.configure(enable_json_logging=True)
+        stream = io.StringIO()
+        logging.getLogger().handlers[0].setStream(stream)
 
         logging.getLogger("uvicorn.access").info("Access log message")
 
-        record = json.loads(capsys.readouterr().err.strip())
+        record = json.loads(stream.getvalue().strip())
         assert record["message"] == "Access log message"
         assert record["logger"] == "uvicorn.access"
         assert record["level"] == "info"
 
     def test_exception_logs_use_json_stacktrace_field(self, capsys):
         """Exception traces should be serialized into a structured stacktrace field."""
         log.configure(enable_json_logging=True)
+        stream = io.StringIO()
+        logging.getLogger().handlers[0].setStream(stream)
 
         try:
             raise RuntimeError("boom")
         except RuntimeError:
             logging.getLogger("uvicorn.error").exception("Request crashed")
 
-        record = json.loads(capsys.readouterr().err.strip())
+        record = json.loads(stream.getvalue().strip())
         assert record["message"] == "Request crashed"
         assert record["logger"] == "uvicorn.error"
         assert "stacktrace" in record