def METHOD_NAME(self):
    f = tempfile.NamedTemporaryFile(delete=False)
    f.close()
    f_with_bom = tempfile.NamedTemporaryFile(delete=False)
    f_with_bom.close()
    with open(f.name, 'w+') as stream:
        stream.write('foo')
    from codecs import open as codecs_open
    with codecs_open(f_with_bom.name, encoding='utf-8-sig', mode='w+') as stream:
        stream.write('foo')
    cases = [
        [['bar=baz'], ['bar=baz']],
        [['bar', 'baz'], ['bar', 'baz']],
        [['bar=@{}'.format(f.name)], ['bar=foo']],
        [['bar=@{}'.format(f_with_bom.name)], ['bar=foo']],
        [['bar', '@{}'.format(f.name)], ['bar', 'foo']],
        [['bar', f.name], ['bar', f.name]],
        [['bar=name@company.com'], ['bar=name@company.com']],
        [['bar', 'name@company.com'], ['bar', 'name@company.com']],
        [['bar=mymongo=@connectionstring'], ['bar=mymongo=@connectionstring']],
        [['bar=@noneexisting'], ['bar=@noneexisting']]
    ]
    for test_case in cases:
        try:
            from azure.cli.core.commands import _expand_file_prefixed_files
            args = _expand_file_prefixed_files(test_case[0])  # pylint: disable=protected-access
            self.assertEqual(args, test_case[1], 'Failed for: {}'.format(test_case[0]))
        except CLIError as ex:
            self.fail('Unexpected error for {} ({}): {}'.format(test_case[0], args, ex))
    os.remove(f.name)