test_main.py 文件源码

def test_image_required(self, capfd):
        """
        When the main function is given no image argument, it should exit with
        a return code of 2 and inform the user of the missing argument.
        """
        with ExpectedException(SystemExit, MatchesStructure(code=Equals(2))):
            main(['--tag', 'abc'])

        out, err = capfd.readouterr()
        assert_that(out, Equals(''))

        # More useful error message added to argparse in Python 3
        if sys.version_info >= (3,):
            # Use re.DOTALL so that '.*' also matches newlines
            assert_that(err, MatchesRegex(
                r'.*error: the following arguments are required: image$',
                re.DOTALL
            ))
        else:
            assert_that(
                err, MatchesRegex(r'.*error: too few arguments$', re.DOTALL))