'JSON file adds to result.'

def test_json_file_userdata(self):

    json_file = FilePath(self.mktemp())
    with json_file.open('w') as f:
        f.write('{"branch":    "master"}\n')
    options = BenchmarkOptions()
    options.parseOptions(['--userdata', '@{}'.format(json_file.path)])
    self.assertEqual(parse_userdata(options), {'branch': 'master'})
