background

file location: projects\storefrontlib\src\cms-components\checkout\components\delivery-mode\delivery-mode.component.html

We are now talking about property binding of “continue” Button’s disabled property.

Expected behavior

Jerry’s observation in unit test

If we change the value of this.mode. Controls [‘ deliveryModeId ‘] TWICE in the same test spec, [disabled] and deliveryModeInvalid will LOSE synchronization, even fixture.detectChanges is called manually.

See my test below.

Paste the following source code to replace your delivery-mode.component.spec.ts and launch it:

import { Component } from '@angular/core';
import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { ReactiveFormsModule } from '@angular/forms';
import { ActivatedRoute } from '@angular/router';
import {
  CheckoutDeliveryService,
  DeliveryMode,
  I18nTestingModule,
} from '@spartacus/core';
import { Observable, of } from 'rxjs';
import { CheckoutConfigService } from '.. /.. /services/checkout-config.service';
import { CheckoutStepService } from '.. /.. /services/checkout-step.service';
import { DeliveryModeComponent } from './delivery-mode.component';
import createSpy = jasmine.createSpy;
import { LoaderState } from '.. /.. /.. /.. /.. /.. /core/src/state/utils/loader';
import { By } from '@angular/platform-browser';

@Component({
  selector: 'cx-spinner'.template: ' ',})class MockSpinnerComponent {}

class MockCheckoutDeliveryService {
  loadSupportedDeliveryModes = createSpy();
  setDeliveryMode = createSpy();
  getSupportedDeliveryModes(): Observable<DeliveryMode[]> {
    return of(a); } getSelectedDeliveryMode(): Observable<DeliveryMode> {return of(a); } getLoadSupportedDeliveryModeProcess(): Observable<LoaderState<void> > {return of();
  }
}

class MockCheckoutConfigService {
  getPreferredDeliveryMode(): string {
    return ' '; }}class MockCheckoutStepService {
  next = createSpy();
  back = createSpy();
  getBackBntText(): string {
    return 'common.back'; }}const mockActivatedRoute = {
  snapshot: {
    url: ['checkout'.'delivery-mode'],}}; describe('DeliveryModeComponent'.() = > {
  let component: DeliveryModeComponent;
  let fixture: ComponentFixture<DeliveryModeComponent>;

  beforeEach(async(() = > {
    TestBed.configureTestingModule({
      imports: [ReactiveFormsModule, I18nTestingModule],
      declarations: [DeliveryModeComponent, MockSpinnerComponent],
      providers: [{provide: CheckoutDeliveryService,
          useClass: MockCheckoutDeliveryService,
        },
        { provide: CheckoutStepService, useClass: MockCheckoutStepService },
        { provide: CheckoutConfigService, useClass: MockCheckoutConfigService },
        { provide: ActivatedRoute, useValue: mockActivatedRoute },
      ],
    }).compileComponents();
  }));

  beforeEach(() = > {
    fixture = TestBed.createComponent(DeliveryModeComponent);
    component = fixture.componentInstance;
    console.log('----------- a new test comes ------------------');
  });


  describe('continue button'.() = >{

    const getContinueBtn = () = > fixture.debugElement.query(By.css('.cx-checkout-btns .btn-primary'));
    const setDeliveryModeId = (value: string) = >  
      component.mode.controls['deliveryModeId'].setValue(value);

    function setDeliveryModeIdNull(){
      setDeliveryModeId(null);
      fixture.detectChanges();
      trace(null);
    }
    function setDeliveryModeIdValid(){
      setDeliveryModeId('a');
      fixture.detectChanges();
      trace('a');
    }

    function trace(id){
      const button = getContinueBtn();
      console.log('************** Delivery Mode id is set as: ' + id + '* * * * * * * * * * * * * *');
      console.log('Flag component.deliveryModeInvalid: ' + 
      component.deliveryModeInvalid + ' button.disabled: ' + button.nativeElement.disabled );
    }

    function valid_then_null(){
      setDeliveryModeIdValid();

      setDeliveryModeIdNull();
    }

    function null_then_valid(){
      setDeliveryModeIdNull();

      setDeliveryModeIdValid();
    }
      
    it('first valid then null'.() = > {
      valid_then_null();
      expect(component).toBeTruthy();
    });

    it('null then valid'.() = > {
      null_then_valid();
      expect(component).toBeTruthy();
    });

    it('only valid'.() = > {
      setDeliveryModeIdValid();
      expect(component).toBeTruthy();
    });

    it('only null'.() = > {
      setDeliveryModeIdNull();
      expect(component).toBeTruthy();
    });
  });
});
Copy the code

In this unit test file I construct four test specs:

(1) set delivery mode id to a valid value first, then set null;

(2) set delivery mode id to null first, then set a valid value to it;

(3) only set a valid value;

(4) only set null;

In each test spec, once I manupulate the value of this.mode.controls[‘ deliveryModeId ‘], then use console.log to display the following pair of values:

• component.deliveryModeInvalid
• button.nativeElement.disabled

In theory the two must always be equal.

Test result

Conclusion

Avoid change delivery mode id TWICE in a single test spec. The case to set id as A in beforeEach and set id as B in a test spec SHOULD also be considered as TWICE, so the two value will lose synchronization as well.

For more of Jerry’s original articles, please follow the public account “Wang Zixi “: