Why Jasmine spy function in Angular is not being triggered by callback?












1















I want to test this.communication.subscribe() call which is having a callback in argument:



constructor (private communication: CommunicationProvider)

ngOnInit() {
this.communication.subscribe(() => {
this.router.navigate(["/success"]);
});
}


I have used callFake to mock the implementation to call callback()



beforeEach(async(() => {
communicationSpy = jasmine.createSpyObj("CommunicationProvider", ["subscribe"]);
routerSpy = jasmine.createSpyObj<Router>("Router", ["navigate"]);

communicationSpy.subscribe.and.callFake((callback: any) => {
callback();
});
}));

it("should route on callback", (done: DoneFn) => {
setTimeout(() => {
expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
done();
}, 3000);
});


As per code coverage results, this.router.navigate(["/success"]); is being covered by callback().
But "should route on callback" test is failing as routerSpy.navigate is never being called.



Why?










share|improve this question





























    1















    I want to test this.communication.subscribe() call which is having a callback in argument:



    constructor (private communication: CommunicationProvider)

    ngOnInit() {
    this.communication.subscribe(() => {
    this.router.navigate(["/success"]);
    });
    }


    I have used callFake to mock the implementation to call callback()



    beforeEach(async(() => {
    communicationSpy = jasmine.createSpyObj("CommunicationProvider", ["subscribe"]);
    routerSpy = jasmine.createSpyObj<Router>("Router", ["navigate"]);

    communicationSpy.subscribe.and.callFake((callback: any) => {
    callback();
    });
    }));

    it("should route on callback", (done: DoneFn) => {
    setTimeout(() => {
    expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
    done();
    }, 3000);
    });


    As per code coverage results, this.router.navigate(["/success"]); is being covered by callback().
    But "should route on callback" test is failing as routerSpy.navigate is never being called.



    Why?










    share|improve this question



























      1












      1








      1








      I want to test this.communication.subscribe() call which is having a callback in argument:



      constructor (private communication: CommunicationProvider)

      ngOnInit() {
      this.communication.subscribe(() => {
      this.router.navigate(["/success"]);
      });
      }


      I have used callFake to mock the implementation to call callback()



      beforeEach(async(() => {
      communicationSpy = jasmine.createSpyObj("CommunicationProvider", ["subscribe"]);
      routerSpy = jasmine.createSpyObj<Router>("Router", ["navigate"]);

      communicationSpy.subscribe.and.callFake((callback: any) => {
      callback();
      });
      }));

      it("should route on callback", (done: DoneFn) => {
      setTimeout(() => {
      expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
      done();
      }, 3000);
      });


      As per code coverage results, this.router.navigate(["/success"]); is being covered by callback().
      But "should route on callback" test is failing as routerSpy.navigate is never being called.



      Why?










      share|improve this question
















      I want to test this.communication.subscribe() call which is having a callback in argument:



      constructor (private communication: CommunicationProvider)

      ngOnInit() {
      this.communication.subscribe(() => {
      this.router.navigate(["/success"]);
      });
      }


      I have used callFake to mock the implementation to call callback()



      beforeEach(async(() => {
      communicationSpy = jasmine.createSpyObj("CommunicationProvider", ["subscribe"]);
      routerSpy = jasmine.createSpyObj<Router>("Router", ["navigate"]);

      communicationSpy.subscribe.and.callFake((callback: any) => {
      callback();
      });
      }));

      it("should route on callback", (done: DoneFn) => {
      setTimeout(() => {
      expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
      done();
      }, 3000);
      });


      As per code coverage results, this.router.navigate(["/success"]); is being covered by callback().
      But "should route on callback" test is failing as routerSpy.navigate is never being called.



      Why?







      angular typescript unit-testing callback jasmine






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 22 '18 at 13:13









      trichetriche

      26k42152




      26k42152










      asked Nov 22 '18 at 13:02









      bhagatbhagat

      618




      618
























          1 Answer
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          0














          Because you never trigger the subscription.



          I don't know what your service is, but we'll take advantage of the fact that you don't use restriction operators such as take or takeUntil.



          Start by mocking your observable as a hot stream with a Subject :



          component['communication'] = new Subject() as any;


          Now, you should have a new instance of your component in every test thanks to the fixture createComponentInstance called in the before each. This means you already have called ngOnInit and created the subscription.



          Since the stream is hot, you can subscribe to it in your test :



          it('should navigate', done => {
          component['communication'].subscribe(() => {
          expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
          done();
          });

          (component['communication'] as Subject).next(true);
          });


          With the next call, you trigger the subscriptions, launching the router and expecting it to have been called.



          (P.S : I have used array syntax and Subject to picture the issue, feel free to use whatever you want to trigger a subscription and to mock your dependencies)






          share|improve this answer























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            1 Answer
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            oldest

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            1 Answer
            1






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            active

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            0














            Because you never trigger the subscription.



            I don't know what your service is, but we'll take advantage of the fact that you don't use restriction operators such as take or takeUntil.



            Start by mocking your observable as a hot stream with a Subject :



            component['communication'] = new Subject() as any;


            Now, you should have a new instance of your component in every test thanks to the fixture createComponentInstance called in the before each. This means you already have called ngOnInit and created the subscription.



            Since the stream is hot, you can subscribe to it in your test :



            it('should navigate', done => {
            component['communication'].subscribe(() => {
            expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
            done();
            });

            (component['communication'] as Subject).next(true);
            });


            With the next call, you trigger the subscriptions, launching the router and expecting it to have been called.



            (P.S : I have used array syntax and Subject to picture the issue, feel free to use whatever you want to trigger a subscription and to mock your dependencies)






            share|improve this answer




























              0














              Because you never trigger the subscription.



              I don't know what your service is, but we'll take advantage of the fact that you don't use restriction operators such as take or takeUntil.



              Start by mocking your observable as a hot stream with a Subject :



              component['communication'] = new Subject() as any;


              Now, you should have a new instance of your component in every test thanks to the fixture createComponentInstance called in the before each. This means you already have called ngOnInit and created the subscription.



              Since the stream is hot, you can subscribe to it in your test :



              it('should navigate', done => {
              component['communication'].subscribe(() => {
              expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
              done();
              });

              (component['communication'] as Subject).next(true);
              });


              With the next call, you trigger the subscriptions, launching the router and expecting it to have been called.



              (P.S : I have used array syntax and Subject to picture the issue, feel free to use whatever you want to trigger a subscription and to mock your dependencies)






              share|improve this answer


























                0












                0








                0







                Because you never trigger the subscription.



                I don't know what your service is, but we'll take advantage of the fact that you don't use restriction operators such as take or takeUntil.



                Start by mocking your observable as a hot stream with a Subject :



                component['communication'] = new Subject() as any;


                Now, you should have a new instance of your component in every test thanks to the fixture createComponentInstance called in the before each. This means you already have called ngOnInit and created the subscription.



                Since the stream is hot, you can subscribe to it in your test :



                it('should navigate', done => {
                component['communication'].subscribe(() => {
                expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
                done();
                });

                (component['communication'] as Subject).next(true);
                });


                With the next call, you trigger the subscriptions, launching the router and expecting it to have been called.



                (P.S : I have used array syntax and Subject to picture the issue, feel free to use whatever you want to trigger a subscription and to mock your dependencies)






                share|improve this answer













                Because you never trigger the subscription.



                I don't know what your service is, but we'll take advantage of the fact that you don't use restriction operators such as take or takeUntil.



                Start by mocking your observable as a hot stream with a Subject :



                component['communication'] = new Subject() as any;


                Now, you should have a new instance of your component in every test thanks to the fixture createComponentInstance called in the before each. This means you already have called ngOnInit and created the subscription.



                Since the stream is hot, you can subscribe to it in your test :



                it('should navigate', done => {
                component['communication'].subscribe(() => {
                expect(routerSpy.navigate).toHaveBeenCalledWith(["/success"]);
                done();
                });

                (component['communication'] as Subject).next(true);
                });


                With the next call, you trigger the subscriptions, launching the router and expecting it to have been called.



                (P.S : I have used array syntax and Subject to picture the issue, feel free to use whatever you want to trigger a subscription and to mock your dependencies)







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 22 '18 at 13:12









                trichetrichetrichetriche

                26k42152




                26k42152






























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