我有一个 python 文件：update_baseline_manifest.py。现在，我正在编写单元测试，想要修补 read_file 和 write_file，我已经这样做了

def update_baseline_manifest(baseline_manifest_path, vbf_info_map, logger):
    """ Updates manifest as per the part numbers in the vbfs_map """
    try:
        manifest_contents = read_file(baseline_manifest_path)
        // Do something


        write_file(manifest_contents, baseline_manifest_path)

def read_file(file_path):
    print('called read')
    with open(file_path, 'r') as file:
        return yaml.safe_load(file)


def write_file(contents, file_path):
    print('called write')
    with open(file_path, 'w') as file:
        yaml.dump(contents, file)

测试文件看起来像

from a.b.update_baseline_manifest import update_baseline_manifest

def test_update_baseline_manifest(self):
    test_contents = 'sample contents'

    with patch('update_baseline_manifest.read_file', return_value=test_contents) as \
        mock_read, patch('update_baseline_manifest.write_file') as mock_write:
        result = update_baseline_manifest(self.args.baseline_manifest_path,
                                            self.args.vbf_info_map,
                                            self.args.logger)

    mock_read.assert_called_with(self.args.baseline_manifest_path)
    mock_write.assert_called_with(contents_written, self.args.baseline_manifest_path)
    self.assertEqual(result, 0)

现在我可以看到我添加的打印，这意味着实际的函数被调用，而模拟的函数没有被调用。如何正确修补它们，以便在导入顶部文件后调用我的模拟函数而不是实际函数？我读了很多关于它的帖子，但我无法理解它。

您需要提供要模拟的函数的完整路径。 参考：https://docs.python.org/3/library/unittest.mock.html#where-to-patch https://docs.python.org/3/library/unittest.mock.html#where-to-patch

    ...
    with patch('a.b.update_baseline_manifest.read_file', return_value=test_contents) as \
mock_read, patch('a.b.update_baseline_manifest.write_file') as mock_write:
    ...