python runtime_error ai_generated true

AssertionError: assert datetime.datetime(2024, 1, 1, 0, 0) == datetime.datetime(2025, 6, 1, 12, 0) # freezegun is active but the imported datetime is the real one

ID: python/pytest-freezegun-datetime-import

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2025-02-08First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.5.x active — — —

Root Cause

The code under test imported datetime as 'from datetime import datetime' before freezegun patched the module, so the test holds a reference to the unpatched class.

generic

中文

被测代码在 freezegun patch 模块之前以 'from datetime import datetime' 方式导入了 datetime，导致测试持有未打补丁的类引用。

Workarounds

  1. 94% success 
    # BAD:  from datetime import datetime
# GOOD: import datetime
then use datetime.datetime.now()

# Test:
from freezegun import freeze_time

@freeze_time('2025-06-01 12:00:00')
def test_x():
    assert get_now() == datetime.datetime(2025, 6, 1, 12, 0)
  2. 80% success 
    import importlib

@freeze_time('2025-06-01')
def test_x():
    import myapp.clock
    importlib.reload(myapp.clock)
    assert myapp.clock.now().year == 2025

Dead Ends

Common approaches that don't work:

  1. 85% fail

    tick only affects the patched clock; the unpatched datetime reference is unaffected and still returns real time.

  2. 92% fail

    Timezone is not the issue; the datetime class itself is not the one freezegun patched.