python runtime_error ai_generated partial

AssertionError: assert datetime.datetime(2025, 1, 15, 10, 30) == datetime.datetime(2024, 6, 1, 0, 0) # expected freeze_time('2024-06-01') to apply

ID: python/pytest-freezegun-time-not-frozen

Also available as: JSON · Markdown · 中文
80%Fix Rate
84%Confidence
0Evidence
2024-09-02First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.5 active — — —

Root Cause

The code under test imported datetime or time functions before freeze_time patched them, or uses a C-extension clock (e.g., time.monotonic_ns via numpy) that freezegun cannot intercept. Also common when the module does 'from datetime import datetime' and freezegun patches the class attribute incorrectly.

generic

中文

被测代码在 freeze_time 修补之前导入了 datetime 或 time 函数，或者使用了 freezegun 无法拦截的 C 扩展时钟（例如通过 numpy 的 time.monotonic_ns）。当模块执行 'from datetime import datetime' 时也常见。

Workarounds

  1. 90% success 
    from freezegun import freeze_time

@freeze_time('2024-06-01')
def test_expiry():
    # myapp/utils.py does: from datetime import datetime
    # freezegun patches datetime.datetime, so this works
    assert is_expired(datetime(2024, 5, 31))
  2. 95% success 
    def is_expired(now=None):
    now = now or datetime.now(timezone.utc)
    return now > EXPIRY

def test_expiry():
    assert is_expired(now=datetime(2024, 5, 31, tzinfo=timezone.utc))

Dead Ends

Common approaches that don't work:

  1. 85% fail

    Nested freezes raise or silently override; the innermost wins, but the outer reference was already captured.

  2. 90% fail

    Sleep does not retroactively patch already-imported names; the test still sees real time.