对 ngx-formly 自定义模板进行单元测试

Question

我正在与Formly合作并创建了几个自定义模板。组件中包含的唯一代码是对通用错误处理服务的调用，因此除了可以创建组件之外，实际上几乎没有什么需要测试的。我仅使用 Jest 进行单元测试，但无法弄清楚需要包含哪些内容才能成功编译组件。

我收到的错误是：TypeError：无法读取未定义的属性“formControl”。我不确定我的测试中缺少什么。

对于最简单的组件（主要是样式和指令 - 现在已删除），我有以下内容：

成分：

@Component({
  selector: 'my-formly-field-input',
  templateUrl: './formly-field-input.component.html',
  styleUrls: ['./formly-field-input.component.scss']
})
export class FormlyFieldInputComponent extends FieldType {

  constructor(private formErrorService: FormErrorHandlerService) {
    super();
  }

  getError(formItem: FormControl | FormGroup | FormArray): string {
    return this.formErrorService.getFormError(formItem);
  }

}

看法：

<mat-form-field [floatLabel]="'always'" 
                class="w-100" 
                [appearance]="'fill'">
    <mat-label>{{field.templateOptions.label}}</mat-label>
    <input matInput 
           [formControl]="formControl"
           [type]="field.templateOptions.type || 'text'"
           [step]="field.templateOptions.step || 1"
           [max]="field.templateOptions.max || undefined"/>
    <mat-error *ngIf="formControl.errors">
        {{getError(formControl)}}
    </mat-error>
</mat-form-field>

单元测试：

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

  const formHelperServiceStub: Partial<FormErrorHandlerService> = {
    getFormError: (formItem) => 'Error Happened'
  };

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        FormlyFieldInputComponent
      ],
      imports: [
        MyHelpersModule,
        BrowserAnimationsModule,
        FormlyModule.forRoot(),
        FormlyMaterialModule,
        MatFormFieldModule,
        MatInputModule,
        ReactiveFormsModule,
      ],
      providers: [
        { provide: FormErrorHandlerService, useValue: formHelperServiceStub }
      ],
    })
    .compileComponents();
  }));

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

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

提前致谢！！

Answer 1

面临类似的问题。我在模拟组件中应用了托管表单的方法。我使用了自定义组件，但我认为这会有所帮助：

@Component({
  selector: 'app-test-cmp',
  template: `
    <form [formGroup]="form">
      <formly-form [model]="{}" [fields]="fields" [options]="{}" [form]="form"></formly-form>
    </form>`
})
class MockFormComponent  {
  form = new FormGroup({ });
  fields: FormlyFieldConfig[] = [{
    wrappers: ['your custom wrapper name'],
    defaultValue: {}
  }];
}

接下来，我在 formly 模块中注册了自定义包装器：

TestBed.configureTestingModule({
      imports: [
        ... Your dependencies will be here,
        FormlyModule.forRoot({
          wrappers: [{'your custom wrapper name', component: FormlyFieldInputComponent}]
        })
       ] 
})

并初始化组件：

beforeEach(() => {
    fixture = TestBed.createComponent(MockFormComponent);
    mockComponent = fixture.componentInstance;
    fixture.detectChanges();
    component = fixture.debugElement.query(By.directive(FormlyFieldInputComponent)).componentInstance;
});