在使用 TestBed 創建模擬組件之前注入數據 - angular 中的單元測試 4

Question

我想在運行之前向DeviceMarkerComponent注入數據：

let component: DeviceMarkerComponent;
let fixture: ComponentFixture<DeviceMarkerComponent>;
...

fixture = TestBed.createComponent(DeviceMarkerComponent);
component = fixture.componentInstance;

ngOnInit在DeviceMarkerComponent中使用變量，我無法在不初始化變量的情況下創建組件。 NgOnInit在調用TestBed.CreateComponent時觸發並導致錯誤，因此我必須設置這些變量或修改我正在測試的代碼:(

Answer 1

在創建組件之前，您需要配置測試平台。 在配置中，您可以設置組件使用的導入，聲明等以及傳遞間諜。

let component: DeviceMarkerComponent;
let fixture: ComponentFixture<DeviceMarkerComponent>;

beforeEach(fakeAsync(() => {
   TestBed.configureTestingModule({
     declarations: [DeviceMarkerComponent],
     providers: [any providers the component uses]
     imports: [any imports component uses]
   }).compileComponents();
}));

beforeEach(() => {
   fixture = TestBed.createComponent(DeviceMarkerComponent);
   component = fixture.componentInstance;
   debugElement = fixture.debugElement;
});

您還可以將Type別名用於測試平台配置，這很有幫助。
https://angular.io/api/core/testing/TestModuleMetadata

Answer 2

    let component: DeviceMarkerComponent;
    let fixture: ComponentFixture<DeviceMarkerComponent>;
    ...
    const testBed = TestBed.configureTestingModule({...});
    // do anything you want to do before createComponent
    testBed.inject(AService).init();
    testBed.compileComponents();
    fixture = TestBed.createComponent(DeviceMarkerComponent);
    component = fixture.componentInstance;

TestBedStatic class下的注入方法文檔。