Unittest+Python接口自动化测试如何进行token关联？

#coding:utf-8
import json
class OperetionJson:

    def __init__(self,file_path=None):
        if file_path  == None:
            self.file_path = '../case/user.json' # 获取的token需要保存的地方
        else:
            self.file_path = file_path
        self.data = self.read_data()

    #读取json文件
    def read_data(self):
        with open(self.file_path, 'r', encoding='utf-8') as fp:
            data1 = fp.read()
            if len(data1) > 0:
                data = json.loads(data1)
            else:
                data = {}
            return data

    #根据关键字获取数据
    def get_data(self,id):
        print(type(self.data))
        return self.data[id]

    #写json
    def write_data(self,data):
        with open('../case/token.json','w') as fp:
            fp.truncate()  # 先清空之前的数据，再写入，这样每次登录的token都是不一样的
            fp.write(json.dumps(data))

if __name__ == '__main__':
    opjson = OperetionJson()
    #print(opjson.get_data('shop'))
    data = {
                "user":"zhang",
                "passwd":123456
            }
    opjson.write_data(data)

import json
import requests
from common.operation_json import OperetionJson

class OperationHeader:

    def __init__(self, response):
        self.response = json.loads(response)

    def get_response_token(self):
        '''
        获取登录返回的token
        '''
        token = {"data":{"token":self.response['data']['token']}}
        #token = {"token": self.response['data']['token']}
        return token
	
	# 把数据写入文件
    def write_token(self):
        op_json = OperetionJson()
        op_json.write_data(self.get_response_token())

    def get_response_msg(self):
        reponse_msg = {"msg":self.response['msg']}
        #print("reponse_msg:", reponse_msg)
        return reponse_msg

if __name__ == '__main__':

	# 一个登录接口数据，仅供参考
    url = "http://192.168.1.117/api/user/login"

    data = {
                "username": "zhang",
                "password": "123456",
                "deviceId": 0
            }

    res = requests.post(url,data).json()
    res1 = json.dumps(res)
    print(type(res1))
    op = OperationHeader(res1)
    print(op.get_response_msg())

class Test_api(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        # 登录获取token
        cls.s = requests.session() # 创建会话
        url = "http://192.168.1.102/api/user/login"
        headers = {"content-type":"application/json","Connection":"keep-alive"}
        data = {"username":"zhang","password":"123456","deviceId":0}
        res = requests.post(url=url, json=data, headers=headers).json()
        res1 = json.dumps(res)
        #print(type(res1))
        op = OperationHeader(res1)
        op.write_token()

        writeexcel.copy_excel(testxlsx, reportxlsx) # 复制xlsx