测试多个路由导致 Jest 模拟 function 未定义

Question

我想知道在 expressJS 中开玩笑地测试多条路线的最佳方法。

我当前的问题是当我尝试测试使用相同模拟 function 的多条路由时，最后一条路由抛出未定义的错误。

这是代码中的上下文。

应用程序.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，test/one.ts 将通过 test/two.ts 将失败并出现错误TypeError: Cannot read property 'query' of undefined referencing this line const result = await db.query(sql)

当我切换 controller 导入时

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

然后test/two.ts通过并且test/one.ts失败并出现相同的错误。 我还想提一下，无论是否重置 jest mock，我都会得到相同的结果。

Answer 1

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

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