Strapi simple unit test

app.test.js

const request = require("supertest");
// function from gist file
const { setupStrapi } = require("./helpers/strapi");

// We're setting timeout because sometimes bootstrap can take 5-7 seconds (big apps)
jest.setTimeout(10000);

let app; // this is instance of the the strapi

beforeAll(async () => {
  app = await setupStrapi(); // return singleton so it can be called many times
});

it("should respond with 200 on /heartbeat", async (done) => {
  request(app.server) // app server is and instance of Class: http.Server
    .get("/heartbeat")
    .expect(200) // expecting response header code to by 200 success
    .expect("Hello World!") // expecting reponse text to be "Hello World!"
    .end(done); // let jest know that test is finished
});