你如何为 python 模块的 argparse 部分编写测试? [英] How do you write tests for the argparse portion of a python module?

问题描述

我有一个使用 argparse 库的 Python 模块.我如何为代码库的那部分编写测试?

I have a Python module that uses the argparse library. How do I write tests for that section of the code base?

推荐答案

你应该重构你的代码并将解析移动到一个函数中:

You should refactor your code and move the parsing to a function:

def parse_args(args):
    parser = argparse.ArgumentParser(...)
    parser.add_argument...
    # ...Create your parser as you like...
    return parser.parse_args(args)

然后在您的 main 函数中，您应该使用以下命令调用它:

Then in your main function you should just call it with:

parser = parse_args(sys.argv[1:])

(其中表示脚本名称的 sys.argv 的第一个元素被删除，以免在 CLI 操作期间将其作为附加开关发送.)

(where the first element of sys.argv that represents the script name is removed to not send it as an additional switch during CLI operation.)

在您的测试中，您可以使用您想要测试的任何参数列表调用解析器函数:

In your tests, you can then call the parser function with whatever list of arguments you want to test it with:

def test_parser(self):
    parser = parse_args(['-l', '-m'])
    self.assertTrue(parser.long)
    # ...and so on.

这样您就不必为了测试解析器而执行应用程序的代码.

This way you'll never have to execute the code of your application just to test the parser.

如果您稍后需要在应用程序中更改和/或向解析器添加选项，请创建一个工厂方法:

If you need to change and/or add options to your parser later in your application, then create a factory method:

def create_parser():
    parser = argparse.ArgumentParser(...)
    parser.add_argument...
    # ...Create your parser as you like...
    return parser

如果您愿意，您可以稍后对其进行操作，并且测试可能如下所示:

You can later manipulate it if you want, and a test could look like:

class ParserTest(unittest.TestCase):
    def setUp(self):
        self.parser = create_parser()

    def test_something(self):
        parsed = self.parser.parse_args(['--something', 'test'])
        self.assertEqual(parsed.something, 'test')

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