python config_error ai_generated true

AssertionError: assert 'processing item' in '' # caplog.text is empty

ID: python/pytest-caplog-propagation-disabled

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
0Evidence
2024-09-27First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
7.x active — — —
8.x active — — —

Root Cause

The application logger has propagate=False set (often to avoid duplicate handlers), so records never reach the root logger that caplog attaches its handler to. caplog captures nothing.

generic

中文

应用 logger 设置了 propagate=False（通常用于避免重复 handler），因此日志记录永远到不了 caplog 挂载 handler 的根 logger。caplog 捕获不到任何内容。

Workarounds

  1. 92% success 
    def test_logs(caplog):
    logger = logging.getLogger('myapp')
    logger.propagate = True
    with caplog.at_level(logging.INFO, logger='myapp'):
        run()
    assert 'processing item' in caplog.text
  2. 88% success 
    def test_logs(caplog):
    logger = logging.getLogger('myapp')
    logger.addHandler(caplog.handler)
    try:
        run()
    finally:
        logger.removeHandler(caplog.handler)
    assert any('processing item' in r.message for r in caplog.records)

Dead Ends

Common approaches that don't work:

  1. 80% fail

    Level is not the problem; propagation is disabled so no records reach caplog regardless of level.

  2. 70% fail

    Logging handlers may not write to stderr, and the format is not the log message alone.