python config_error ai_generated true

AssertionError: assert 'expected log' in []

ID: python/pytest-caplog-no-capture

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
0Evidence
2024-09-10First Seen

Version Compatibility

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

Root Cause

caplog captures via logging's root logger by default; if the code under test uses a custom logger with propagate=False or a different handler, caplog sees nothing.

generic

中文

caplog 默认通过 logging 的根 logger 捕获；若被测代码使用 propagate=False 的自定义 logger 或其他 handler，caplog 看不到任何内容。

Workarounds

  1. 90% success 
    def test_logs(caplog):
    logger = logging.getLogger('myapp.worker')
    logger.propagate = True
    with caplog.at_level(logging.INFO):
        run_worker()
    assert 'expected log' in caplog.text
  2. 85% success 
    def test_logs(caplog):
    logger = logging.getLogger('myapp.worker')
    logger.addHandler(caplog.handler)
    run_worker()
    assert 'expected log' in caplog.text

Dead Ends

Common approaches that don't work:

  1. 85% fail

    Sets the level but does not fix propagation; if propagate=False, records still never reach caplog's handler.

  2. 80% fail

    Adds a root handler but caplog replaces handlers per test; custom loggers with propagate=False still bypass.

  3. 90% fail

    capsys captures stdout/stderr; logging output may not be written there depending on handler configuration.