javascript - 在这种情况下，在 Jest 中测试 axios 函数的正确方法是什么？

Question

我已经编写了一个基本的测试用例来测试我的 axios 功能。测试用例失败。我正在尝试测试一个 axios 调用，它让我得到一个 json。我格式化该数据并解析 Promise 函数。开 Jest 给出了错误，TypeError: Cannot read property 'then' of undefined

`

TypeError: 无法读取未定义的属性 'then'

  67 |                 'Authorization': `Bearer ${accessToken}`,
  68 |             },
> 69 |         }).then((response: any): any => {
     |           ^
  70 |             if (response.statusText === "OK") {
  71 |                 return Promise.resolve(response.data);
  72 |             }

`

模拟/axios.ts

export default {
    get: jest.fn(() => Promise.resolve()),
    request: jest.fn(() => Promise.resolve())
};

//libHelper.tsx

export default class libHelper{
    constructor() {
        // parameters initialization
        }
    }

    public fetchMsGraph = (accessToken: string): Promise<GraphData> => {
        return axios.get(Constants.someURL, {
            headers: {
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${accessToken}`,
            },
        }).then((response: any): any => {
            if (response.statusText === "OK") {
                return Promise.resolve(response.data);
            }
            else {
                return Promise.reject(Error(`API Response not OK`));
            }
        }).catch((err: any): any => Promise.reject(Error(`Fetch API Error ${err}`)));

    }

//libHelper-tests.tsx

import libHelper from "../Scripts/libHelper";
import axios from "../__mocks__/axios";
import { UserDataGen1, Data } from "../Scripts/interfaces";

describe("", (): void => {

    test("basic test", () => {
        let msalobject: MsalHelper = new MsalHelper();
        expect(msalobject).toBeInstanceOf(MsalHelper);
    });

    test("not so basic", async () => {
        const resp: UserDataGen1 = {
            idp: "string",
            memberName: "string",
            lastName: "string",
            firstName: "string",
            cid: "string",
            authenticatedState: "string",
            picture: "string"
        }
        axios.get.mockImplementation(() => { Promise.resolve(resp); });

        let libObject: libHelper = new libHelper();
        const rand: Data = await libObject.fetchAPP("asd");

        expect(rand).toEqual(resp);
    });
});

Answer 1

你应该使用mockResolvedValue:

       const resp: UserDataGen1 = {
            idp: "string",
            memberName: "string",
            lastName: "string",
            firstName: "string",
            cid: "string",
            authenticatedState: "string",
            picture: "string"
        }
        axios.get.mockResolvedValue(resp);