Unit test async method with multiple awaits

Issue

I am trying to test statements after 1st await but it doesn’t work. Debugger doesn’t hit the next breakpoint

service.ts

async deleteFaq(faq: FaqDetailsApi) {
  await this._http.delete(`${this.ADMIN_FAQ_URL}/${faq.id}`).toPromise();

  debugger // Debugger doesn't hit this, next lines are not executed

  await this._http.get(`${this.ADMIN_FAQ_URL}/${faq.order}/-1/${faq.id}`).toPromise();
  const faqPrev = this._faqs.getValue().find(f => f.id === faq.id);
}

service.spec.ts

it('should create a DELETE request 123', fakeAsync(() => {
  let faq = testFaqs[0];
  service.deleteFaq(faq);
  const req = httpMock.expectOne(`${service.ADMIN_FAQ_URL}/${faq.id}`);
  tick();
  expect(req.request.method).toBe('DELETE'); // pass
  const req2 = httpMock.expectOne(`${service.ADMIN_FAQ_URL}/${faq.order}/-1/${faq.id}`);
  tick();
  expect(req2.request.method).toBe('GET'); // fails
}));

Solution

In order to proceed execution after await your need to fulfill two things:

• resolve and complete Observable by simulating http request
• simulate the asynchronous passage of Promise

You already use tick() that solves the second case but it does nothing without simulating http request.

Use TestRequest#flush method for that:

const req = httpMock.expectOne(`${service.ADMIN_FAQ_URL}/${faq.id}`);
req.flush({}); // synchrounously simulates http request and complete observable
tick();
...

Answered By – yurzui

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