如何对使用 Popen 的函数进行单元测试? [英] How to unit test a function that uses Popen?

问题描述

我正在编写一个包含大量文件操作的程序.有些操作是通过调用subprocess.Popen来完成的，例如，split -l 50000 ${filename}, gzip -d -f ${filename} ${filename}..

I am writing a program which contains a lot of file operation. Some operations are done by calling subprocess.Popen, eg, split -l 50000 ${filename}, gzip -d -f ${filename} ${filename}..

现在我想对程序的功能进行单元测试.但是我如何对这些函数进行单元测试?

Now I want to unit test the functionality of the program. But how could I unit test these functions?

有什么建议吗?

推荐答案

规范的方法是模拟对 Popen 的调用并用一些测试数据替换结果.查看mock 库文档.¹

The canonical way is to mock out the call to Popen and replace the results with some test data. Have a look at the mock library documentation.¹

你会做这样的事情:

with mock.patch.object(subprocess, 'Popen') as mocked_popen:
    mocked_popen.return_value.communicate.return_value = some_fake_result
    function_which_uses_popen_communicate()

现在你可以做一些检查或任何你想测试的......

Now you can do some checking or whatever you want to test...

^{1请注意，这在python3.3中作为unittest.mock包含在标准库中.}

^{1Note that this was included in the standard library as unittest.mock in python3.3.}

这篇关于如何对使用 Popen 的函数进行单元测试?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！