Jest doesn't exit properly

Question

When running this integration test with Jest in nodeJS:

const request = require("supertest");
let server;

describe("/api/chat", () => {
  beforeEach(() => {
    server = require("../../api");
  });
  describe("GET /userlist", () => {
    it("show userlist", async () => {
      const result = await request(server)
        .get("/api/chat/userlist")
        .set("X-Auth", process.env.XAuth);
      expect(result.status).toBe(200);
    });
  });
  afterAll(done => {
    server.close(done);
  });
});

With the api.js file:

const PORT = process.env.PORT;

const server = app.listen(PORT, () => {
  console.log(`listening on port ${PORT}`);
});

app.use("/api/chat", chat);

module.exports = server;

I get an an error, that it something keeps it up from exiting:

Jest has detected the following 1 open handle potentially keeping Jest from exiting:

  ●  TCPSERVERWRAP

      21 | const PORT = process.env.PORT;
      22 | 
    > 23 | const server = app.listen(PORT, () => {
         |                    ^
      24 |   console.log(`listening on port ${PORT}`);
      25 | });
      26 | 

Any ideas? I checked already on Github but nothing really helped or was just a workaround. How can I properly close the connection?

Answer 1

I have just started using jest and after few experiments, the following worked for me.

Modify app.js as follows during testing,

const PORT = process.env.PORT;

// COMMENT THESE
// const server = app.listen(PORT, () => {
//  console.log(`listening on port ${PORT}`);
// });

app.use("/api/chat", chat);

module.exports = app; // EXPORT app

and on test file use supertest as follows,

// IMPORT app HERE ARE USE IT AS FOLLOWS
await request(app)
        .post("/api/chat")
        .set("Content-Type", "application/json")
        .send({ ...your_payload });

And lastly close db connection,

afterAll(done => {
  // THIS IS HOW YOU CLOSE CONNECTION IN MONGOOSE (mongodb ORM)
  mongoose.connection.close();
  done();
});