python runtime_error ai_generated true

AssertionError: 未找到期望的调用。 期望: fetch('https://api.example.com') 实际: fetch()

AssertionError: expected call not found. Expected: fetch('https://api.example.com') Actual: fetch()

ID: python/unittest-mock-magicmock-assertion

其他格式: JSON · Markdown 中文 · English
80%修复率
86%置信度
0证据数
2024-08-03首次发现

版本兼容性

版本状态引入弃用备注
3.8 active — — —
3.12 active — — —

根因分析

assert_called_with 比较精确的位置参数和关键字参数。实际调用传入了不同的参数（例如 URL 对象而非字符串），或者 mock 在调用和断言之间被重置/重新配置。

English

assert_called_with compares exact positional and keyword arguments. The actual call passed different arguments (e.g., a URL object instead of a string) or the mock was reset/reconfigured between the call and the assertion.

generic

解决方案

  1. 90% 成功率 
    mock_fetch.assert_called_once()
args, kwargs = mock_fetch.call_args
assert str(args[0]) == 'https://api.example.com'
  2. 82% 成功率 
    from unittest.mock import call, ANY
mock_fetch.assert_called_with(ANY)
assert mock_fetch.call_args.args[0].__str__().endswith('/api.example.com')

无效尝试

常见但无效的做法:

  1. 80% 失败

    Only checks call count, not arguments; the bug (wrong URL) goes undetected.

  2. 85% 失败

    matching.ANY makes the assertion always pass and hides the real argument mismatch.