Issue
I'm working on an Angular application and I have a directive where I create a position strategy using the Angular CDK Overlay. Here's a simplified version of my code:
const positionStrategy = this.overlay
.position()
.flexibleConnectedTo(this.elementRef)
.withPositions([
{
originX: 'center',
originY: 'bottom',
overlayX: 'center',
overlayY: 'top',
},
])
.withFlexibleDimensions(false)
.withTransformOriginOn('.test')
.withPush(false);
positionStrategy.positionChanges.subscribe((change: ConnectedOverlayPositionChange) => {
// My code here
});
I want to write a unit test to ensure that the subscription inside positionStrategy.positionChanges is working as expected. However, I'm having trouble covering this part of my code in the unit test.
Can someone please help me write a unit test that covers the subscription and allows me to test the behavior of the code inside the subscription?
I've already tried to create a test case, but I'm not sure how to mock or spy on the positionStrategy and trigger a position change to test the subscription.
Any guidance or examples of how to set up the unit test for this scenario would be greatly appreciated. Thank you!
Solution
Testing Angular CDK Overlay's positionChanges
subscription can be a bit tricky, but it's doable. To test this, you need to create a mockup of OverlayRef
and ConnectedPositionStrategy
.
import { Component, Directive, ElementRef } from '@angular/core';
import { Overlay, OverlayRef } from '@angular/cdk/overlay';
import { ConnectedPositionStrategy } from '@angular/cdk/overlay';
import { TestBed, ComponentFixture, async } from '@angular/core/testing';
import { MyDirective } from './my.directive'; // Import your directive
@Directive({
selector: '[myDirective]',
})
class MyDirectiveMock extends MyDirective {
constructor(
elementRef: ElementRef,
overlay: Overlay,
) {
super(elementRef, overlay);
}
}
@Component({
template: `
<div myDirective></div>
`,
})
class TestComponent {}
describe('MyDirective', () => {
let fixture: ComponentFixture<TestComponent>;
let overlay: Overlay;
let overlayRef: OverlayRef;
let connectedPositionStrategy: jasmine.SpyObj<ConnectedPositionStrategy>;
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [MyDirectiveMock, TestComponent],
providers: [
Overlay,
],
}).compileComponents();
fixture = TestBed.createComponent(TestComponent);
overlay = TestBed.inject(Overlay);
// Create a spy object for ConnectedPositionStrategy
connectedPositionStrategy = jasmine.createSpyObj<ConnectedPositionStrategy>('ConnectedPositionStrategy', ['withPositions', 'withFlexibleDimensions', 'withTransformOriginOn', 'withPush']);
overlayRef = jasmine.createSpyObj<OverlayRef>('OverlayRef', ['dispose']);
overlayRef.getConfig.and.returnValue({ positionStrategy: connectedPositionStrategy });
}));
it('should handle position strategy changes', () => {
// Create an instance of your directive
const directiveInstance = fixture.debugElement.query(By.directive(MyDirectiveMock)).injector.get(MyDirectiveMock);
// Manually trigger a position change
connectedPositionStrategy.positionChanges.next({} as ConnectedOverlayPositionChange);
// Assert that your code inside the subscription has been called or test its behavior
// For example, you can check if a method was called in your directive
expect(directiveInstance.someMethod).toHaveBeenCalled();
});
});
Answered By - Mohamed Oussema Njimi
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