unit testing a promise method that implements .toPromise() on an http call

[Kiflemariam Andom]

My method is simply like this in angular 5:

  public login(data): Promise<any> {
    const vm : any = this;

    return new Promise((resolve, reject) => {
      let url ="www.example.com"
      vm.http.post(url, data).toPromise().then(
        resp => {
          resolve(resp);
        }).catch(err=>{
          reject(err)
        })
    });
  }

The URL is usually dependent on the body but let's just assme it is example.com for now. I want to write a unit test that ensures an http call was made to a given url but for now, it just says "found none" and fails:

it("should login user", fakeAsync(() => {

    let response = {
      resultCount: 1    
    };

    service
    .login(
     {'name':'name'}
    )
    .then(result => {
      expect(result).toEqual(response);
    });

    flushMicrotasks();


    // Expect a call to this URL
      const req = httpTestingController.expectOne(
      "www.example.com"
    );
    expect(req.request.method).toEqual("POST");
    req.flush(response);
    tick();

  }));

How do i unit test the method. It is driving me crazy.