Problem: I would like to be able to unit test a directive in Angular 2 to make sure that it properly compiles.
In Angular 1, it was possible to use$compile(angular.element(myElement)
service and call $scope.$digest()
after that. I specifically want to be able to do this in unit tests so I could test that when Angular ends up running across <div my-attr-directive/>
in the code that my-attr-directive
compiles.
Constraints:
Let's say you have a following directive:
@Directive({
selector: '[my-directive]',
})
class MyDirective {
public directiveProperty = 'hi!';
}
What you have to do, is to create a component that uses the directive (it can be just for testing purpose):
@Component({
selector: 'my-test-component',
template: ''
})
class TestComponent {}
Now you need to create a module that has them declared:
describe('App', () => {
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [
TestComponent,
MyDirective
]
});
});
// ...
});
You can add the template (that contains directive) to the component, but it can be handled dynamically by overwriting the template in test:
it('should be able to test directive', async(() => {
TestBed.overrideComponent(TestComponent, {
set: {
template: '<div my-directive></div>'
}
});
// ...
}));
Now you can try to compile the component, and query it using By.directive
. At the very end, there is a possibility to get a directive instance using the injector
:
TestBed.compileComponents().then(() => {
const fixture = TestBed.createComponent(TestComponent);
const directiveEl = fixture.debugElement.query(By.directive(MyDirective));
expect(directiveEl).not.toBeNull();
const directiveInstance = directiveEl.injector.get(MyDirective);
expect(directiveInstance.directiveProperty).toBe('hi!');
});
To test a directive you need to create a fake component with it:
@Component({
selector: 'test-cmp',
directives: [MyAttrDirective],
template: ''
})
class TestComponent {}
You can add the template in the component itself but it can be handled dynamically by overwriting the template in test:
it('Should setup with conversation', inject([TestComponentBuilder], (testComponentBuilder: TestComponentBuilder) => {
return testComponentBuilder
.overrideTemplate(TestComponent, `<div my-attr-directive></div>`)
.createAsync(TestComponent)
.then((fixture: ComponentFixture<TestComponent>) => {
fixture.detectChanges();
const directiveEl = fixture.debugElement.query(By.css('[my-attr-directive]'));
expect(directiveEl.nativeElement).toBeDefined();
});
}));
Note that you're able to test what directive renders but I couldn't find the way to test a directive in a way components are (there is no TestComponentBuilder for directives).