测试多条路由导致Jest mock函数未定义

Question

我想知道用jest在expressJS中测试多条路由的最佳方法。

我目前的问题是，当我尝试测试多个路由使用相同的模拟函数，最后一个路由抛出一个未定义的错误。

下面是代码中的上下文。

app.ts

import * as express from "express";
import controllerOne from "./controllers/one";
import controllerTwo from "./controllers/two";
const app = express();
app.use("/one", controllerOne);
app.use("/two", controllerTwo);
export default app;

控制器/one.ts

import getDbConnection from "../db";
import * as express from "express";
const router = express.Router();
const db = getDbConnection();
router.get("/", async (_, res) => {
const sql = "SELECT * from table";
const result = await db.query(sql);
res.status(200).json(result);
});
export default router;

控制器/two.ts

import getDbConnection from "../db";
import * as express from "express";
const router = express.Router();
const db = getDbConnection();
router.get("/", async (_, res) => {
const sql = "SELECT * from table";
const result = await db.query(sql);
res.status(200).json(result);
});
export default router;

测试/one.ts

import * as request from "supertest";
import { mocked } from "ts-jest/utils";
import db from "../db";
jest.mock("../db");
const mockedDB = mocked(db);
const data = ["data"];
describe("Controller One", () => {
afterAll(() => {
jest.restoreAllMocks();
jest.resetModules();
});
beforeEach(() => {
const mockedQueryFn = {
query: jest.fn().mockResolvedValueOnce(data),
};
mockedDB.mockReturnValueOnce(mockedQueryFn);
});
it("should retrieve one", async () => {
const mod = require("../src/app");
const app = (mod as any).default;
await request(app)
.get("/one")
.expect(200)
.expect(function (res) {
expect(res.body).toEqual(data);
});
});
});

测试/two.ts

import * as request from "supertest";
import { mocked } from "ts-jest/utils";
import db from "../db";
jest.mock("../db");
const mockedDB = mocked(db);
const data = ["data"];
describe("Controller One", () => {
afterAll(() => {
jest.restoreAllMocks();
jest.resetModules();
});
beforeEach(() => {
const mockedQueryFn = {
query: jest.fn().mockResolvedValueOnce(data),
};
mockedDB.mockReturnValueOnce(mockedQueryFn);
});
it("should retrieve one", async () => {
const mod = require("../src/app");
const app = (mod as any).default;
await request(app)
.get("/two")
.expect(200)
.expect(function (res) {
expect(res.body).toEqual(data);
});
});
});

现在我的问题是如果我运行测试，测试/1。t会通过测试2。ts将失败，错误TypeError: Cannot read property 'query' of undefined引用这行const result = await db.query(sql)

切换控制器导入时

import controllerTwo from "./controllers/two";
import controllerOne from "./controllers/one";

则test/two.ts通过，test/one.ts失败，错误相同。我还想提到，有/没有重置jest mock，我得到相同的结果。

Answer 1

这可能与您在测试结束时没有调用done这一事实有关。在测试的expect部分中，调用done()。您还需要更改回调，使其像这样:

it("should retrieve one", async (done) => {