Angular执行测试报错: Can't bind to 'ngModel' since it isn't a known property of 'input'

本是古典何须时尚 2022-04-11 11:00 570阅读 0赞

Angular执行测试报错: Can’t bind to ‘ngModel’ since it isn’t a known property of ‘input’

本机环境：

$ ng --version
    Angular CLI: 7.1.1
    Node: 10.11.0
    OS: darwin x64
    Angular: 7.1.1
    ... animations, cli, common, compiler, compiler-cli, core, forms
    ... http, language-service, platform-browser
    ... platform-browser-dynamic, router
    
    Package                           Version
    -----------------------------------------------------------
    @angular-devkit/architect         0.10.6
    @angular-devkit/build-angular     0.10.6
    @angular-devkit/build-optimizer   0.10.6
    @angular-devkit/build-webpack     0.10.6
    @angular-devkit/core              7.0.6
    @angular-devkit/schematics        7.1.1
    @ngtools/webpack                  7.0.6
    @schematics/angular               7.1.1
    @schematics/update                0.11.1
    rxjs                              6.3.3
    typescript                        3.1.6
    webpack                           4.19.1

执行 `ng test` 报错，错误内容如下：

Chrome 72.0.3622 (MacOSX 10.13.6) HeroeDetailComponent should create FAILED
      Can't bind to 'ngModel' since it isn't a known property of 'input'. ("
    <div>
    <label>name:
      <input [ERROR ->][(ngModel)]="heroDetail.name" placeholder="name"/>
    </label>
    </div>
    "): ng:///DynamicTestModule/HeroDetailComponent.html@10:15

使用 `ng serve` 运行应用，通过访问 `http://localhost:4200`,都一切正常。  
为何在执行测试用例会报错呢？

查看 `app.module.ts`文件，已经导入了表单模块：

@NgModule({
      declarations: [ ... ],
      imports: [
        AppRoutingModule,
        BrowserModule,
        FormsModule,
        HttpClientModule,
      ],
      providers: [],
      bootstrap: [AppComponent]
    })
    export class AppModule { }

在 `app.module.ts` 中已经都引入了表单模块 `FormsModule`，所以访问应用都正常。但是测试执行测试用例时，没有找到表单模块。

解决办法，在测试用例文件`hero-detail.component.spec.ts`的`beforeEach`部分，引入表单模块 `FormsModule` :

beforeEach(async(() => {
        TestBed.configureTestingModule({
          declarations: [ HeroDetailComponent ],
          imports:[ 
            RouterTestingModule, 
            HttpClientTestingModule, 
            FormsModule 
          ]
        }).compileComponents();
      }));

完整代码如下：

// hero-detail.component.spec.ts`
    import { async, ComponentFixture, TestBed } from '@angular/core/testing';
    
    import { HeroDetailComponent } from './hero-detail.component';
    import { RouterTestingModule } from '@angular/router/testing';
    import { HttpClientTestingModule } from '@angular/common/http/testing';
    import { FormsModule } from '@angular/forms';
    
    describe('HeroeDetailComponent', () => {
      let component: HeroDetailComponent;
      let fixture: ComponentFixture<HeroDetailComponent>;
    
      beforeEach(async(() => {
        TestBed.configureTestingModule({
          declarations: [ HeroDetailComponent ],
          imports:[ 
            RouterTestingModule, 
            HttpClientTestingModule, 
            FormsModule 
          ]
        })
        .compileComponents();
      }));
    
      beforeEach(() => {
        fixture = TestBed.createComponent(HeroDetailComponent);
        component = fixture.componentInstance;
        fixture.detectChanges();
      });
    
      it('should create', () => {
        expect(component).toBeTruthy();
      });
    });

更多内容，查看完整代码：  
[https://github.com/cnwyt/angular-tour-of-heroes][https_github.com_cnwyt_angular-tour-of-heroes]

\[END\]

[https_github.com_cnwyt_angular-tour-of-heroes]: https://github.com/cnwyt/angular-tour-of-heroes