我正在用Angular 8和NativeScript编写一个应用程序。我正在将一些表单构建到我的应用程序中，我想为表单编写单元测试。

以下是一些代码段：

register.html

    <StackLayout class="input-field">
        <Label text="Client Code"></Label>
        <TextField 
            required 
            class="input" 
            [class.is-invalid]="clientCodeField.invalid && clientCodeField.dirty"
            [(ngModel)]="clientcode" 
            #clientCodeField="ngModel">
        </TextField>
        <StackLayout class="hr-light"></StackLayout>
    </StackLayout>

register.component.spec.ts

import { RegisterClientCodeComponent } from './register-client-code.component';
import { ComponentFixture,TestBed } from '@angular/core/testing';
import { NativeScriptFormsModule } from 'nativescript-angular/forms';

describe('RegisterClientCodeComponent',() => {

    let component: RegisterClientCodeComponent;
    let fixture: ComponentFixture<RegisterClientCodeComponent>;

    beforeEach(() => {

        // refine the test module by declaring the test component
        TestBed.configureTestingModule({
            imports: [NativeScriptFormsModule],declarations: [RegisterClientCodeComponent]
        });

        fixture = TestBed.createComponent(RegisterClientCodeComponent);
        component = fixture.componentInstance;
        component.ngOnInit();
    });

    it(' RegisterClientCodeComponent should be defined',() => {
        expect(component).toBeDefined();
    });

    it(' RegisterClientCodeComponent should be defined',() => {
        //let email = component.form.controls['email'];
        //expect(email.valid).toBeFalsy();
    });
});

但是，在单元测试中说组件没有“ form”部分。如何编写我的单元测试以检查表单是否有效？