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[英]Angular2 - Error: Can't resolve all parameters for IconService
[英]Angular2 Component test - Error: Can't resolve all parameters
我正在第一次使用Karma / Jasmine等工具測試我的一個組件,並且一直關注測試文檔 。 我的組件需要3個構造函數參數。
constructor(
private myService: MyService,
private renderer: Renderer,
private element: ElementRef
) { }
我已經嘗試根據文檔的這一部分來模擬/存根那些依賴關系,如下所示;
// Mocks/Stubs
const myServiceStub = {};
class MockElementRef {}
class MockRenderer {}
// beforeEach block
beforeEach(() => {
TestBed.configureTestingModule({
declarations: [ MyComponent ],
providers: [
{ provide: ElementRef, useClass: MockElementRef },
{ provide: Renderer, useClass: MockRenderer },
{ provide: MyService, useValue: myServiceStub},
]
});
fixture = TestBed.createComponent(MyComponent);
});
盡管如此,每當我運行測試時,都會出現以下錯誤;
Error: Can't resolve all parameters for MyComponent: (?, ?, ?).
at SyntaxError.ZoneAwareError (test.ts:9250:33)
at SyntaxError.BaseError [as constructor] (test.ts:44243:16)
at new SyntaxError (test.ts:44453:16)
at CompileMetadataResolver._getDependenciesMetadata (test.ts:61503:31)
我在這里想念什么? 謝謝!
它可能是由循環DI引起的,請嘗試將您的組件MyComponent重構為注入服務,如下所示:
constructor(@Inject(forwardRef(() => MyComponentService)) private myService: MyComponentService) {}
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