如果 Nock 按特定顺序运行多次测试，则不会拦截请求

Question

I'm creating some unit test for my endpoint. This endpoint will fetch data from an external API and send diff responses depending on finding a certain item on that data fetched or if there is an error fetching data from that external API.

I have 2 unit test, one makes a call to the external API and the other I mock it with nock to intercept that external API call and send back an error. The problem: When I run both inside describe, the one which I used nock fails. If I run both test separated, they both succeed. If I reorder the unit test, putting the one with the nock first and the other second, they both pass. I read and tried some solutions related to nock and didn't work.

here is the unit test:

 describe("x endpoint testing", () => {
    afterEach("Restore Nocks", async (done) => {
        if (nock.isActive()) {
            nock.cleanAll();
            nock.restore();
        }
        done();
    });

    it("should return 200", (done) => {
        chai
            .request(server)
            .get(`/endpoint/${realParams}`)
            .set("Content-Type", "application/json")
            .send()
            .then((res) => {
                res.should.have.status(200);
                done();
            })
            .catch(done);
    });

    it("should return 400 if a connection error occur with API", (done) => {
        if (!nock.isActive()) nock.activate();

        const apiNock = nock(process.env.API_ENDPOINT)
            .log(console.log)
            .get(`/api`)
            .replyWithError({
                message: "Something awful happened",
                code: "404",
            });

        chai
            .request(server)
            .get(`/endpoint/${fakeParams}`)
            .set("Content-Type", "application/json")
            .send()
            .then((res) => {
                expect(apiNock.isDone()).to.be.true;
                res.should.have.status(400);
                res.body.should.have.property("error");
                done();
            })
            .catch(done);
    });
});

Answer 1

I usually prefer to outline exactly what the issues are in your example, however, I think issues lay outside the provided code. Instead, here is some code that runs and passes no matter which order the tests are run.

My hope is that you can compare this with the rest of your project and easily identify what is amiss.

const chai = require("chai")
const chaiHttp = require('chai-http')
const nock = require("nock")
const http = require("http")

const API_ENDPOINT = 'http://postman-echo.com'

chai.use(chaiHttp);
const server = http.createServer((request, response) => {
  const outReq = http.get(`${API_ENDPOINT}/get?foo=${request.url}`, () => {
    response.end()
  });

  outReq.on("error", err => {
    response.statusCode = 400;
    response.write(JSON.stringify({error: err.message}))
    response.end()
  })
});

describe("endpoint testing", () => {
  afterEach((done) => {
    nock.cleanAll();
    done();
  });

  it("should return 200", (done) => {
    chai
      .request(server)
      .get(`/endpoint/live`)
      .set("Content-Type", "application/json")
      .send()
      .then((res) => {
        chai.expect(res.status).to.equal(200);
        done();
      })
      .catch(done);
  });

  it("should return 400 if a connection error occur with API", (done) => {
    const apiNock = nock(API_ENDPOINT)
      .get('/get?foo=/endpoint/fake')
      .replyWithError({
        message: "Something awful happened",
        code: "404",
      });

    chai
      .request(server)
      .get(`/endpoint/fake`)
      .set("Content-Type", "application/json")
      .send()
      .then((res) => {
        chai.expect(apiNock.isDone()).to.be.true;
        chai.expect(res.status).to.equal(400);
        chai.expect(res.text).to.equal('{"error":"Something awful happened"}');
        done();
      })
      .catch(done);
  });
});