我想在django中的views.py中打开json文件进行单元测试

def get_json_data():
    json_data = json.load(open(JSON_DIRECTORY+'my.json'))
    return json_data

请帮助我如何单元测试json文件是否加载

def test_read_file_data(self):

    def read_file_data(filename, path):
        os.chdir(path)
        with open(filename,  encoding="utf8") as data_file:
            json_data = json.load(data_file)
        return json_data

    sample_json = {

    }
    sample_json = json.dumps(sample_json, ensure_ascii=False)
    path = my file path
    filename = real file
    self.assertEqual(read_file_data(filename, path), sample_json)

在json中也有null，所以我不知道如何处理null