在测试用例中，需要为组件的输入属性提供值。如果未提供，输入属性将为undefined，因此当组件尝试读取该属性时会出现此错误。以下是一个示例：

组件代码：

@Component({ selector: 'app-my-component', templateUrl: './my-component.component.html' }) export class MyComponentComponent { @Input() myInput: string;

getValue(): string { return this.myInput.value; //此处出现TypeError } }

测试用例代码：

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

beforeEach(async () => { await TestBed.configureTestingModule({ declarations: [ MyComponentComponent ] }) .compileComponents(); });

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

it('should get value', () => { component.myInput = {value: 'test'}; //为输入属性myInput提供值 expect(component.getValue()).toEqual('test'); }); });