Mocking BsModalRef for Unit Testing - unit-testing

I am using the BsModalRef for showing modals and sending data using the content property. So we have some like this :
this.followerService.getFollowers(this.bsModalRef.content.channelId).subscribe((followers) => {
this.followerList = followers;
this.followerList.forEach((follower) => {
follower.avatarLink = this.setUserImage(follower.userId);
this.followerEmails.push(follower.email);
});
});
We are setting the channelId in content of bsModalRef (this.bsModalRef.content.channelId). It is working fine. Now i am writing a unit test for this. Problem is i am not able to mock it. I have tried overriding, spy etc but nothing seems to work. I am using the approach mentioned in this link. One alternative is to use TestBed but i am not much aware of its use. Can anyone please help me finding any approach by which this can be achieved ?

I recently had to do something similar and Mocking the method call worked. The tricky part is injecting the BsModalService in both the test suite and the component.
describe('MyFollowerService', () => {
configureTestSuite(() => {
TestBed.configureTestingModule({
imports: [...],
declarations: [...],
providers: [...]
}).compileComponents();
});
// inject the service
beforeEach(() => {
bsModalService = getTestBed().get(BsModalService);
}
it('test', () => {
// Mock the method call
bsModalService.show = (): BsModalRef => {
return {hide: null, content: {channelId: 123}, setClass: null};
};
// Do the test that calls the modal
});
});
As long as you're calling bsModal as follows this approach will work
let bsModalRef = this.modalService.show(MyChannelModalComponent));
Finally, here are some links that have more indepth coverage about setting up the tests with TestBed.
https://chariotsolutions.com/blog/post/testing-angular-2-0-x-services-http-jasmine-karma/
http://angulartestingquickstart.com/
https://angular.io/guide/testing

Related

jasmine serivce function not returning mock value

I am work on the angular testing for first time and from monring i struggling to test this. I added both modules inside TestBed and injected but real method is always called instead of returning value from getMockFeatureState(). Please help fix this. Thannks
beforeEach(() => {
TestBed.configureTestingModule({
imports: [ HttpClientModule ],
providers: [ FeatureToggleService, ConfigService]
});
});
it('should return values based on mock feature state', () => {
const featureService = TestBed.inject(FeatureToggleService);
const configService = TestBed.inject(ConfigService);
const mockFeaturesSpy = spyOn(configService, 'getMockFeatures')
.and.returnValue(getMockFeatureState());
expect(featureService.isFeatureEnabled('feature1')).toBeFalsy();
expect(featureService.isFeatureEnabled('feature2')).toBeFalsy();
});
I recently faced the same issue in one of my tests. The order of TestBed.inject was the issue. If FeatureToggleService requires ConfigService. You have to inject ConfigService first and mock it before injecting the featureService. You can try
it('should return values based on mock feature state', () => {
const configService = TestBed.inject(ConfigService);
const mockFeaturesSpy = spyOn(configService, 'getMockFeatures')
.and.returnValue(getMockFeatureState());
const featureService = TestBed.inject(FeatureToggleService);
expect(featureService.isFeatureEnabled('feature1')).toBeFalsy();
expect(featureService.isFeatureEnabled('feature2')).toBeFalsy();
});
I also moved the injection of dependency service into beforeEach block like mentioned in other answer so that it can be applied for other tests too

React Native: Jest mocking Platform

When writing unit tests for a React Native project I want to be able to test different snapshots based on different platforms.
I first tried jest.mock to mock Platform but seems to be async. This approach does work when I have two separate files, but I'd prefer to keep everything in one file if possible.
I tried jest.doMock because of this snippet from the documentation:
When using babel-jest, calls to mock will automatically be hoisted to the top of the code block. Use this method if you want to explicitly avoid this behavior.
https://facebook.github.io/jest/docs/en/jest-object.html#jestdomockmodulename-factory-options
However I'm still seeing undesirable results. When I console.log in the android test I see that Platform.OS is whatever I set the first doMock to be.
I also tried wrapping the mock in a beforeEach in a describe becasue I thought that might help with scoping
http://facebook.github.io/jest/docs/en/setup-teardown.html#scoping
describe('ios test', () => {
it('renders ui correctly', () => {
jest.doMock('Platform', () => {
const Platform = require.requireActual('Platform');
Platform.OS = 'ios';
return Platform;
});
const wrapper = shallow(<SomeComponent />);
const tree = renderer.create(wrapper).toJSON();
expect(tree).toMatchSnapshot();
});
});
describe('android test', () => {
it('renders ui correctly', () => {
jest.doMock('Platform', () => {
const Platform = require.requireActual('Platform');
Platform.OS = 'android';
return Platform;
});
const wrapper = shallow(<SomeComponent />);
const tree = renderer.create(wrapper).toJSON();
expect(tree).toMatchSnapshot();
});
});
Any ideas on how I can change the mock Platform for tests in the same file?
There are a lot of suggestions on how to solve this problem in another question, but none of them worked for me either, given the same requirements you have (tests for different OSs in the same suite file and in one test run).
I eventually worked around it with a somewhat clunky trivial helper function that can be mocked as expected in tests – something like:
export function getOS() {
return Platform.OS;
}
Use it instead of Platform.OS in your code, and then simply mock it in your tests, e.g.
it('does something on Android', () => {
helpers.getOS = jest.fn().mockImplementationOnce(() => 'android');
// ...
}
That did the trick; credit for the idea is due to this guy.

Angular2 Component Unit Testing with Service Dependency

So I have this PromptComponent and the content will be updated by a service data.
Now I am trying to do the unit test this component which has this service dependency.
Here is the Component:
export class PromptComponent {
#Input() module: any;
#select() selectedPrompt;
constructor(private moduleService: ModuleService){}
}
Here is the service:
getQuote(): Promise<string> {
return new Promise(resolve => {
setTimeout( () => resolve(this.nextQuote()), 500 );
});
}
private nextQuote() {
if (this.next === quotes.length) { this.next = 0; }
return quotes[ this.next++ ];
}
Here is the unit test code:
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [
PromptComponent,
],
providers: [ ModuleService]
});
fixture = TestBed.createComponent(PromptComponent);
component = fixture.componentInstance;
const moduleService = fixture.debugElement.injector.get(ModuleService);
spy = spyOn(moduleService, 'getQuote').and.returnValue(Promise.resolve(testService));
I referred to the official demo on the angular documentation
https://angular.io/resources/live-examples/testing/ts/eplnkr.html, as inside the TwainComponent.spec.
Something really weird is that as expected, inside the official demo, the TwainComponent test passed smoothly. But I, on the other hand, got this strange injectionError. If I remove the parameter inside the constructor, I am able to create the fixture instance but get injection error when it runs thorught the injector.get() part. But as soon as I put the private moduleService:ModuleService back inside the component constructor, I will get fixture undefined and also with the injection error.
So that means I cannot even execute my code to the actual service injection part (fixture.debugElement.injector.get(ModuleService)), I already got the error.
Does anybody have the same issue?
My code is almost identical to the demo code on Plunker. Have no clue how to move forward....

Angular 2: How to mock ChangeDetectorRef while unit testing

I have just started with Unit-Testing, and I have been able to mock my own services and some of Angular and Ionic as well, but no matter what I do ChangeDetectorRef stays the same.
I mean which kind of sorcery is this?
beforeEach(async(() =>
TestBed.configureTestingModule({
declarations: [MyComponent],
providers: [
Form, DomController, ToastController, AlertController,
PopoverController,
{provide: Platform, useClass: PlatformMock},
{
provide: NavParams,
useValue: new NavParams({data: new PageData().Data})
},
{provide: ChangeDetectorRef, useClass: ChangeDetectorRefMock}
],
imports: [
FormsModule,
ReactiveFormsModule,
IonicModule
],
})
.overrideComponent(MyComponent, {
set: {
providers: [
{provide: ChangeDetectorRef, useClass: ChangeDetectorRefMock},
],
viewProviders: [
{provide: ChangeDetectorRef, useClass: ChangeDetectorRefMock},
]
}
})
.compileComponents()
.then(() => {
let fixture = TestBed.createComponent(MyComponent);
let cmp = fixture.debugElement.componentInstance;
let cdRef = fixture.debugElement.injector.get(ChangeDetectorRef);
console.log(cdRef); // logs ChangeDetectorRefMock
console.log(cmp.cdRef); // logs ChangeDetectorRef , why ??
})
));
it('fails no matter what', async(() => {
spyOn(cdRef, 'markForCheck');
spyOn(cmp.cdRef, 'markForCheck');
cmp.ngOnInit();
expect(cdRef.markForCheck).toHaveBeenCalled(); // fail, why ??
expect(cmp.cdRef.markForCheck).toHaveBeenCalled(); // success
console.log(cdRef); // logs ChangeDetectorRefMock
console.log(cmp.cdRef); // logs ChangeDetectorRef , why ??
}));
#Component({
...
})
export class MyComponent {
constructor(private cdRef: ChangeDetectorRef){}
ngOnInit() {
// do something
this.cdRef.markForCheck();
}
}
I have tried everything , async, fakeAsync, injector([ChangeDetectorRef], () => {}).
Nothing works.
Update 2020:
I wrote this originally in May 2017, it's a solution that worked great at the time and still works.
We can't configure the injection of a changeDetectorRef mock through the test bed, so this is what I am doing these days:
it('detects changes', () => {
// This is a unique instance here, brand new
const changeDetectorRef = fixture.debugElement.injector.get(ChangeDetectorRef);
// So, I am spying directly on the prototype.
const detectChangesSpy = spyOn(changeDetectorRef.constructor.prototype, 'detectChanges');
component.someMethod(); // Which internally calls the detectChanges.
expect(detectChangesSpy).toHaveBeenCalled();
});
Then you don't care about private attributes or any.
In case anyone runs into this, this is one way that has worked well for me:
As you are injecting the ChangeDetectorRef instance in your constructor:
constructor(private cdRef: ChangeDetectorRef) { }
You have that cdRef as one of the private attributes on the component, which means you can spy on the component, stub that attribute and have it return whatever you want. Also, you can assert its calls and parameters, as needed.
In your spec file, call your TestBed without providing the ChangeDetectorRef as it won't provide what you give it. Set the component that same beforeEach block, so it is reset between specs as it is done in the docs here:
component = fixture.componentInstance;
Then in the tests, spy directly on the attribute
describe('someMethod()', () => {
it('calls detect changes', () => {
const spy = spyOn((component as any).cdRef, 'detectChanges');
component.someMethod();
expect(spy).toHaveBeenCalled();
});
});
With the spy you can use .and.returnValue() and have it return whatever you need.
Notice that (component as any) is used as cdRef is a private attribute. But private doesn't exist in the actual compiled javascript so it is accessible.
It is up to you if you want to access private attributes at runtime that way for your tests.
Not sure if this a new thing or not, but changeDetectorRef can be accessed via fixture.
See docs: https://angular.io/guide/testing#componentfixture-properties
We ran into the same issue with change detector mocking and this is ended up being the solution
Probably one point that needs to be pointed out, is that in essence here you want to test your own code, not unit test the change detector itself (which was tested by the Angular team).
In my opinion this is a good indicator that you should extract the call to the change detector to a local private method (private as it is something you don't want to unit test), e.g.
private detectChanges(): void {
this.cdRef.detectChanges();
}
Then, in your unit test, you will want to verify that your code actually called this function, and thus called the method from the ChangeDetectorRef. For example:
it('should call the change detector',
() => {
const spyCDR = spyOn((cmp as any).cdRef, 'detectChanges' as any);
cmp.ngOnInit();
expect(spyCDR).toHaveBeenCalled();
}
);
I had the exact same situation, and this was suggested to me as a general best practice for unit testing from a senior dev who told me that unit testing is actually forcing you by this pattern to structure your code better. With the proposed restructuring, you make sure your code is flexible to change, e.g. if Angular changes the way they provide us with change detection, then you will only have to adapt the detectChanges method.
For unit testing, if you are mocking ChangeDetectorRef just to satisfy dependency injection for a component to be creation, you can pass in any value.
For my case, I did this:
TestBed.configureTestingModule({
providers: [
FormBuilder,
MyComponent,
{ provide: ChangeDetectorRef, useValue: {} }
]
}).compileComponents()
injector = getTestBed()
myComponent = injector.get(MyComponent)
It will create myComponent successfully. Just make sure test execution path does not need ChangeDetectorRef. If you do, then replace useValue: {} with a proper mock object.
In my case, I just needed to test some form creation stuff using FormBuilder.
// component
constructor(private changeDetectorRef: ChangeDetectorRef) {}
public someHandler() {
this.changeDetectorRef.detectChanges();
}
// spec
const changeDetectorRef = fixture.componentRef.changeDetectorRef;
jest.spyOn(changeDetectorRef, 'detectChanges');
fixture.detectChanges(); // <--- needed!!
component.someHandler();
expect(changeDetectorRef.detectChanges).toHaveBeenCalled();

How to test Angular2's router.navigate?

I've run into missing <router-outlet> messages in other unit tests, but just to have a nice isolated example, I created an AuthGuard that checks if a user is logged in for certain actions.
This is the code:
canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) {
if (!this.authService.isLoggedIn()) {
this.router.navigate(['/login']);
return false;
}
return true;
}
Now I want to write a unit test for this.
This is how I start my test:
beforeEach(() => {
TestBed.configureTestingModule({
imports: [
RouterTestingModule.withRoutes([
{
path: 'login',
component: DummyComponent
}
])
],
declarations: [
DummyComponent
],
providers: [
AuthGuardService,
{
provide: AuthService,
useClass: MockAuthService
}
]
});
});
I created a DummyComponent that does nothing.
Now my test. Pretend that the service returns false and that it triggers this.router.navigate(['/login']):
it('should not let users pass when not logged in', (): void => {
expect(authGuardService.canActivate(<any>{}, <any>{})).toBe(false);
});
This will throw an exception with "Cannot find primary outlet to load".
Obviously I can use toThrow() instead of toBe(false), but that doesn't seem like a very sensible solution. Since I'm testing a service here, there is no template where I can put the <router-outlet> tag. I could mock the router and make my own navigate function, but then what's the point of RouterTestingModule? Perhaps you even want to check that navigation worked.
I could mock the router and make my own navigate function, but then what's the point of RouterTestingModule? Perhaps you even want to check that navigation worked.
There's no real point. If his is just a unit test for the auth guard, then just mock and spy on the mock to check that it's navigate method was called with the login argument
let router = {
navigate: jasmine.createSpy('navigate')
}
{ provide: Router, useValue: router }
expect(authGuardService.canActivate(<any>{}, <any>{})).toBe(false);
expect(router.navigate).toHaveBeenCalledWith(['/login']);
This is how unit tests should normally be written. To try to test any actual real navigation, that would probably fall under the umbrella of end-to-end testing.
If you want to test the router without mocking it you can just inject it into your test and then spy directly on the navigate method there. The .and.stub() will make it so the call doesn't do anything.
describe('something that navigates', () => {
it('should navigate', inject([Router], (router: Router) => {
spyOn(router, 'navigate').and.stub();
expect(authGuardService.canActivate(<any>{}, <any>{})).toBe(false);
expect(router.navigate).toHaveBeenCalledWith(['/login']);
}));
});
this worked for me
describe('navigateExample', () => {
it('navigate Example', () => {
const routerstub: Router = TestBed.get(Router);
spyOn(routerstub, 'navigate');
component.navigateExample();
});
});
it(`editTemplate() should navigate to template build module with query params`, inject(
[Router],
(router: Router) => {
let id = 25;
spyOn(router, "navigate").and.stub();
router.navigate(["/template-builder"], {
queryParams: { templateId: id }
});
expect(router.navigate).toHaveBeenCalledWith(["/template-builder"], {
queryParams: { templateId: id }
});
}
));
I came up with something like that:
describe('TestComponent', () => {
let component: TestComponent;
let router: Router;
let fixture: ComponentFixture<TestComponent>;
const routerSpy = jasmine.createSpyObj('Router', ['navigate']); // create a router spy
beforeEach(async(() => {
TestBed.configureTestingModule({
imports: [
HttpClientTestingModule
],
declarations: [TestComponent],
providers: [
{ provide: Router, useValue: routerSpy } // use routerSpy against Router
],
}).compileComponents();
}));
beforeEach(() => {
router = TestBed.inject(Router); // get instance of router
fixture = TestBed.createComponent(TestComponent);
component = fixture.componentInstance;
fixture.detectChanges();
});
it(`should navigate to 'home' page`, () => {
component.navigateToHome(); // call router.navigate
const spy = router.navigate as jasmine.Spy; // create the navigate spy
const navArgs = spy.calls.first().args[0]; // get the spy values
expect(navArgs[0]).toBe('/home');
});
});
Inspired with angular docs: https://angular.io/guide/testing-components-scenarios#routing-component
I am new to unit testing angular/javascript apps. I needed a way to mock (or spy) for my unit test. The following line is borrowed from Experimenter and helped me TREMENDOUSLY!
const routerSpy = jasmine.createSpyObj('Router', ['navigate']); // create a router spy
I would like to say that I had no idea I could do that with Jasmine. Using that line above, allowed me to then create a spy on that object and verify it was called with the correct route value.
This is a great way to do unit testing without the need to have the testbed and all the ceremony around getting the testing module setup. Its also great because it still allows me to have a fake router object with out the need to stub in all of the parameters, methods, etc etc etc.