错误:< toHaveBeenCalled> :可能是间谍，但未定义

问题描述

我收到一个预期的Spy错误，但在我的angular 10测试中未定义.我正在使用茉莉花和业力.我已经将服务SpreadsheetService嘲笑为mockSpreadSheetService.我正在调用它的方法.我不明白为什么它会期待间谍.

I am getting an error expected Spy but got undefined in my angular 10 test. I am using Jasmine and Karma. I have mocked the service SpreadsheetService as mockSpreadSheetService. I am calling the its method. I fail to understand why its expecting a spy.

我想到的一个可能原因是在运行测试之前创建了mockSpreadSheetService，并且我们正在调用component.ngOnit，这可能会重新创建组件实例.我试图在component.ngOnit之后显式创建模拟服务，但仍然无法正常工作.

One possible reason i could think of is that mockSpreadSheetService gets created before running the test and we are calling component.ngOnit which possible recreates the component instance. I tried to explicitly create the mockservice after component.ngOnit but it still didnt work.

我的问题理想情况下，我们应该在模拟对象上进行测试.为什么需要间谍.

My question Ideally we should be testing on the mock object. Why is spy needed.

expect(mockSpreadSheetService.loadXML).toHaveBeenCalled();

TestComponent

TestComponent

 let component: SpreadsheetComponent;
  let fixture: ComponentFixture<SpreadsheetComponent>;
  let mockSpreadSheetService;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
        imports: [HttpClientTestingModule],
        declarations: [SpreadsheetComponent],
        providers: [{SpreadsheetService, useFactory: () =>   mockSpreadSheetService.Object}]
      })
      .compileComponents();
  }));

  beforeEach(() => {

    mockSpreadSheetService = new Mock<SpreadsheetService>({
      loadXML: () => of(xmlData)
    });

    fixture = TestBed.createComponent(SpreadsheetComponent);
    component = fixture.componentInstance;
    //fixture.detectChanges();

  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });

  it('should call loadXML when ngOnInit is called', fakeAsync(() => {
   // spyOn(component.spreadsheetService, 'loadXML');
    component.ngOnInit();
    tick();
    expect(mockSpreadSheetService.loadXML).toHaveBeenCalled();
  }));
});

主要组成部分

 ngOnInit(): void {
    this.spreadsheetService.loadXML().subscribe((data) => {
      this.parseXML(data)
        .then((data) => {
          console.log('data is ' , data);
          this.xmlItems = data;
        });
    });
  }

推荐答案

间谍未正确创建.

这是它的外观:

let component: SpreadsheetComponent;
  let fixture: ComponentFixture<SpreadsheetComponent>;
  let mockSpreadSheetService;

  beforeEach(async(() => {
    mockSpreadSheetService = jasmine.createSpyObj(['loadXML']);
    mockSpreadSheetService.loadXML.and.returnValue(of());

    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      declarations: [SpreadsheetComponent],
      providers: { provide: SpreadsheetService, useValue: mockSpreadSheetService }
    });

    fixture = TestBed.createComponent(SpreadsheetComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();

  }));

  it('should create', () => {
    expect(component).toBeTruthy();
  });

  it('should call loadXML when ngOnInit is called', () => {
    component.ngOnInit();
    expect(mockSpreadSheetService.loadXML).toHaveBeenCalled();
  });
});

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