How do I write test cases to cover the lines within subsribe callback function

Question

In my component, I have this code:

setTakenNcatsNames(): void {
    if (this.settings.route){

    this.dataService.getAll(this.settings.route).subscribe(result => 
    {
            console.log('in herer');
            this.arrTakenNcatsNames = result
        });
    }
}

How do I write test cases to cover the lines within the .subscribe() callback? My lines within the .subscribe always show up as not covered no matter what I try.[2]

My coverage always show me this:

`

setTakenNcatsNames(): void {
        Eif (this.settings.route){
            this.dataService.getAll(this.settings.route).subscribe(result => {
                **console.log('in herer');**
                **this.arrTakenNcatsNames = result**
            });
        }
    }

`

Here is my test case for it, what am I missing here?

describe('setTakenNcatsNames()', () => {
    fit('sets the array for taken NCATS names', fakeAsync(() => {
        component.setTakenNcatsNames();
    }));
});

because your subscription has never reached! can you add more code so I can help you with it — Aravind, May 14 '20 at 22:05

score 0 · Accepted Answer · answered May 15 '20 at 06:50

0

add spy for dataService.getAll

fit('sets the array for taken NCATS names', fakeAsync(() => {
    const service: DataService = TestBed.get(DataService);
    spyOn(service, "getAll").and.returnValue(of('test');// create a mock result instead of test
    component.setTakenNcatsNames();
    expect(component.arrTakenNcatsNames ).toBe('test');// or mock result 
    }));

This way you can test the block under subscribe

answered May 15 '20 at 06:50

Shlok Nangia

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Oh my god, thank you so much, I spent so much time trying to figure this out. I got the lines covered now. – Van Le May 15 '20 at 15:16
happy to help :-), please accept the answer if it helped, thank you. – Shlok Nangia May 16 '20 at 07:28
Thank you very much, I have accepted the answer. :-) – Van Le Jun 09 '20 at 20:20

How do I write test cases to cover the lines within subsribe callback function

1 Answers1