这个错误通常意味着在测试过程中出现了一个无法注入的依赖项。你需要检查你的测试代码并确保所有的依赖项都被正确注入。以下是一些可能的

1. 检查你的测试代码和被测试的代码，确保它们之间的依赖关系正确。
2. 确保你使用了正确的装饰器来注入依赖项。即@Inject或@ViewChild等。
3. 确保你正确导入依赖项所在的模块。
4. 如果你在测试环境中使用了Providers，请确保它们包含了被注入的依赖项。
5. 如果你的代码依赖于服务，请使用createSpyObj或jasmine.createSpy来创建一个模拟对象。

示例代码：

// app.component.ts import { Component, OnInit } from '@angular/core'; import { MyService } from './my.service';

@Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.scss'] }) export class AppComponent implements OnInit { title = 'my-app'; public msg: string;

constructor(private myService: MyService) {}

ngOnInit() { this.msg = this.myService.getMessage(); } }

// app.component.spec.ts import { TestBed, async } from '@angular/core/testing'; import { AppComponent } from './app.component'; import { MyService } from './my.service';

describe('AppComponent', () => { beforeEach(async(() => { TestBed.configureTestingModule({ declarations: [ AppComponent ], providers: [MyService] }).compileComponents(); }));

it('should create the app', () => { const fixture = TestBed.createComponent(AppComponent); const app = fixture.debugElement.componentInstance; expect(app).toBeTruthy(); });

it(should have as title 'my-app', () => { const fixture = TestBed.createComponent(AppComponent); const app = fixture.debugElement.componentInstance; expect(app.title).toEqual('my-app'); });

it(should have a message 'Hello World', () => { const myService = TestBed.inject(MyService); spyOn(myService, 'getMessage').and.returnValue('Hello World'); const fixture = TestBed.createComponent(AppComponent); const app = fixture.debugElement.componentInstance; fixture.detectChanges(); expect(app.msg).toEqual('Hello World'); }); });