Angular9中使用FormGroup时测试引擎失败

Question

我有以下组件：

export class BaseFormComponent implements OnInit {
  basicFormGroup: FormGroup;
  constructor(
    protected basicProviderService: BasicProviderService,
    protected formBuilder: FormBuilder,
    protected dialog: MatDialog,
    protected spinner: NgxSpinnerService
    ) {
    this.basicFormGroup = this.formBuilder.group({
      name:[''],
      note: ['', Validators.required],
      description: ['', Validators.required]
    });
  }
}

其模板代码：

<h3><span>Basic form data</span></h3>
<mat-divider></mat-divider>
<form *ngIf="true" [formGroup]="basicFormGroup">
<!-- its content does not matter-->
</form>

这是测试：

fdescribe('BasicFormComponent', () => {
  let component: BasicFormComponent;
  let fixture: ComponentFixture<BasicFormComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [BasicFormComponent],
      imports: [
        FormsModule,
        MatDialogModule,
        MatAutocompleteModule,
        MatSnackBarModule,
        MatExpansionModule,
        MatStepperModule,
        MatFormFieldModule,
        TextFieldModule,
        MatInputModule,
        MatDatepickerModule,
        MatNativeDateModule,
        MatListModule,
        MatSelectModule,
        HttpClientTestingModule,
        RouterTestingModule,
        BrowserAnimationsModule,
        CoreModule
      ],
      providers: [
        { provide: BasicProviderService, useClass: BasicProviderServiceStub }
      ]
    })
      .compileComponents();
  }));

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

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});

当它运行时，调用 createComponent 方法时出现以下错误：

HeadlessChrome 80.0.3987 (Windows 10.0.0) BasicFormComponent should create FAILED
        Error: NodeInjector: NOT_FOUND [ControlContainer]
            at getOrCreateInjectable (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:5467:1)
            at Module.ɵɵdirectiveInject (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:20759:1)
            at NodeInjectorFactory.NgControlStatusGroup_Factory [as factory] (http://localhost:9877/_karma_webpack_/node_modules/@angular/forms/__ivy_ngcc__/fesm2015/forms.js:1013:135)
            at getNodeInjectable (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:5598:1)
            at instantiateAllDirectives (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:12645:1)
            at createDirectivesInstances (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:11881:1)
            at ɵɵelementStart (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:20943:1)
            at BasicFormComponent_Template (ng:///BasicFormComponent.js:192:9)
            at executeTemplate (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:11841:1)
            at renderView (http://localhost:9877/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:11627:1)
        Expected undefined to be truthy.
            at UserContext.<anonymous> (http://localhost:9877/_karma_webpack_/src/app/basic-form/basic-form.component.spec.ts:62:23)
            at ZoneDelegate.invoke (http://localhost:9877/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:365:1)
            at ProxyZoneSpec.onInvoke (http://localhost:9877/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:305:1)
            at ZoneDelegate.invoke (http://localhost:9877/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:364:1)
HeadlessChrome 80.0.3987 (Windows 10.0.0): Executed 1 of 181 (1 FAILED) (0 secs / 0.293 secs)

我尝试了以下方法：

当我使用 ngIf='false' 时，测试成功 --> 所以它可能因为形式
当我将 [formGroup]='basicFormGroup'属性替换为 [formGroup]='undefined' 时，测试失败 --> 因此它以 any 形式失败

app.module.ts 文件包含 FormsModule 导入。

看来测试引擎找不到表单的抽象基。

这可能是什么原因造成的？

Answer 1

反应式表单需要 ReactiveFormsModule 才能导入，模板驱动表单需要 FormsModule.

此处您使用的是 formGroup 指令，它是反应形式的一部分，因此需要 ReactiveFormsModule。

参考angular docs这两种形式的区别

Angular9中使用FormGroup时测试引擎失败

Test engine failure when FormGroup is used in Angular 9

testing

typescript

angular

angular9