Angular 单元测试是否根据来自服务的数据调用组件方法

Question

我不知道如何测试组件方法是否在服务数据条件下被触发...

服务看起来像：

@Injectable()
export class SomeService {

    someData() {
        return true;
    }
}

补偿：

export class SomeComponent {

    constructor(private someService: SomeService) { 

        if (this.someService.someData()) {
            this.someMethod();
        } else {
            console.log('keep kalm!');
        }
    }

    someMethod() {
        console.log('some method is fired!')
    }
}

测试：

describe('SomeComponent', () => {
    let component: SomeComponent;
    let fixture: ComponentFixture<SomeComponent>; 

    let mockSomeService = {
        someData: () => true
    }

    beforeEach(async(() => {
        TestBed.configureTestingModule({
            declarations: [SomeComponent],
            providers: [
                {
                    provide: SomeService, useValue: mockSomeService
                }
            ]
        })
        .compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(SomeComponent);
        component = fixture.componentInstance;
        fixture.detectChanges();
    });

    it('method should be called', () => {
        spyOn(component, 'someMethod'); 

        expect(component.someMethod).toHaveBeenCalled(); 
    });
});

组件 someMethod 触发但测试失败：

预期间谍 someMethod 已被调用。

我怎样才能解决这个问题？

提前致谢！

Answer 1

好的它是固定的！感谢@Supamiu 的回答

以防将来有人需要它：

将初始化移动到 ngOnInit 中，移除 fixture.detectChanges(); 从 beforeEach 并在测试中执行它。所以：

比较：

constructor(private someService: SomeService) { }

ngOnInit() {
    if (this.someService.someData()) {
        this.someMethod();
    } else {
        console.log('keep kalm!');
    }
}

测试：

beforeEach(() => {
    fixture = TestBed.createComponent(SomeComponent);
    component = fixture.componentInstance;
    // fixture.detectChanges(); <<< Remove this
});

it('method should be called', () => {
    spyOn(component, 'someMethod'); 
    fixture.detectChanges(); // trigger ngOnInit here

    expect(component.someMethod).toHaveBeenCalled(); 
});

Answer 2

你设置间谍太晚了。当您安装 spy on service 时，它​​已经被构建someMethod并被调用。所以在defining组件调用spy之后

it('method should be called', () => {
        var spy = spyOn(component, "someMethod").and.callThrough();
        expect(component).toBeDefined();
        expect(spy);
        expect(component.someMethod).toHaveBeenCalled(); 
 });