Question

我想修补exists()对象的pathlib.Path方法以进行单元测试，但我无法解决此问题。

我想做的是：

from unittest.mock import patch
from pathlib import Path

def test_move_basic():
    p = Path('~/test.py')
    with patch.object(p, 'exists') as mock_exists:
        mock_exists.return_value = True

但它失败了：

AttributeError: 'PosixPath' object attribute 'exists' is read-only。

有什么想法吗？

Answer 1

您需要修补类，而不是实例。在Select 'various' from TourDet Inner join TourHdr on TourDet.tourhdrid = TourHdr.id Inner join DietAnal on DietAnal.ddtourid = TourHdr.id and DietAnal.ddtourtype = 'TourHdr' (IF TourHdr.paxnos = TourDet.paxnos) OR Inner join DietAnal on DietAnal.ddtourid = TourDet.id and DietAnal.ddtourtype = 'TourDet' (IF TourHdr.paxnos = TourDet.paxnos)类上修补方法就足够了，因为它为整个Path库（exists，pathlib定义了PosixPath方法， WindowsPath和PurePosixPath都继承了实现）：

PureWindowsPath

>>> from unittest.mock import patch >>> from pathlib import Path >>> p = Path('~/test.py') >>> with patch.object(Path, 'exists') as mock_exists: ... mock_exists.return_value = True ... p.exists() ... True >>> with patch.object(Path, 'exists') as mock_exists: ... mock_exists.return_value = False ... p.exists() ... False >>> with patch.object(Path, 'exists') as mock_exists: ... mock_exists.return_value = 'Anything you like, actually' ... p.exists() ... 'Anything you like, actually'类使用__slots__来保持内存占用率低，这会导致其实例的副作用不支持任意属性赋值。

如何修补`pathlib.Path.exists（）`方法？

1 个答案: