[英]Event emitter in Angular unit test isn't called
鉴于此组件...
export class MyComponent {
@Output() onActivateEditMode = new EventEmitter<boolean>();
constructor() {}
emitActivateEditMode(flag: boolean) {
this.onActivateEditMode.emit(flag);
}
...而这个模板...
<a (click)="emitActivateEditMode(true)" data-test-start-edit-project-btn>Edit</a>
...然后此测试失败:
describe('MyComponent', () => {
... (TestBed imports etc)
beforeEach(() => {
fixture = TestBed.createComponent(MyComponent);
component = fixture.componentInstance;
spyOn(component, 'emitActivateEditMode');
fixture.detectChanges();
});
it('should activate editmode on click', () => {
const onActivateEditModeSpy = jest.spyOn(
component.onActivateEditMode,
'emit'
);
const startEditProjectBtn = fixture.debugElement.nativeElement.querySelector(
'[data-test-start-edit-project-btn]'
);
startEditProjectBtn.dispatchEvent(new Event('click')); // startEditProjectBtn.click() doesn't change the result, too
fixture.detectChanges();
expect(component.onActivateEditMode.emit).toHaveBeenCalledWith(true);
// expect(onActivateEditModeSpy).toHaveBeenCalledWith(true) ... doesn't change the result, too
});
});
测试 output 为:
Expected: true
Number of calls: 0
该功能在浏览器中有效,但此测试设置中的某些内容是错误的。
我假设您同时使用 Jasmine 和 Jest。 问题是,当您监视 function ( spyOn
) 时,您实际上只是在监视 function 的调用和实现细节 Z34D1F91FB2E514B9576FAB1A75A 要获得完整的实现细节,您可以执行spyOn(component, 'emitActivateEditMode').and.callThrough();
但我认为对你来说,它是不需要的。
describe('MyComponent', () => {
... (TestBed imports etc)
beforeEach(() => {
fixture = TestBed.createComponent(MyComponent);
component = fixture.componentInstance;
// remove the mock/spyOn to the function emitActivateEditMode
fixture.detectChanges();
});
it('should activate editmode on click', () => {
// spy on emit calls on onActivatedEditMode
const emitSpy = spyOn(component.onActivateEditMode, 'emit');
const startEditProjectBtn = fixture.debugElement.nativeElement.querySelector(
'[data-test-start-edit-project-btn]'
);
startEditProjectBtn.click();
fixture.detectChanges(); // fixture.detectChanges is not needed here, only if you want to see the update in the HTML.
expect(emitSpy).toHaveBeenCalledWith(true);
});
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