Angular2如何对自定义验证器指令进行单元测试？

Question

我为输入字段编写了一个非常简单的自定义验证器：

import { Directive } from '@angular/core';
import { AbstractControl, NG_VALIDATORS } from '@angular/forms';

function numberValidator(c: AbstractControl) {
    if (!c.value) return null;
    return new RegExp('^[1-9][0-9]{6,9}$').test(c.value) ? null : {
        validateNumber: {
            valid: false
        }
    }
}

@Directive({
    selector: '[number-validator]',
    providers: [
        { provide: NG_VALIDATORS, multi: true, useValue: numberValidator }
    ]
})
export class NumberValidator {}

我想对这个验证器进行单元测试。我在 Angular2 页面上阅读了Test an attribute directive，但没有 css 或 html 发生变化。如何对这个验证器进行单元测试？

Answer 1

如果你想用简单的方法（我会这样做，因为所有逻辑都在验证器函数中），只是测试验证器函数。只需将控件传递给它

expect(numberValidator(new FormControl('123456'))).toEqual({
  'validateNumber': { 'valid': false }
});
expect(numberValidator(new FormControl('123456789'))).toEqual(null);

如果你真的想在“被使用”时测试它，那么它会变得有点乏味。这些通常是我采取的步骤

1. 创建虚拟组件以使用指令
2. 设置测试台配置
3. 创建要测试的组件。
4. 获取本机输入元素并向其分派无效输入事件
5. 获取持有NgForm的注射器
6. 检查表单是否失败
7. 输入一个有效的输入并检查它是否通过。

与仅测试验证器方法相比，这要多得多。但无论如何它都在这里 ;-) 享受吧！

import { Component, Directive } from '@angular/core';
import { TestBed, async } from '@angular/core/testing';
import { dispatchEvent } from '@angular/platform-browser/testing/browser_util';
import { By } from '@angular/platform-browser';
import { FormsModule, NG_VALIDATORS, AbstractControl,
         NgForm, FormControl } from '@angular/forms';

function numberValidator(c: AbstractControl) {
  if (!c.value) return null;
  return new RegExp('^[1-9][0-9]{6,9}$').test(c.value) ? null : {
    validateNumber: {
      valid: false
    }
  };
}

@Directive({
  selector: '[number-validator]',
  providers: [
    { provide: NG_VALIDATORS, multi: true, useValue: numberValidator }
  ]
})
export class NumberValidator {
}

@Component({
  template: `
    <form>
      <input name="number" type="text" ngModel number-validator />
    </form>
  `
})
class TestComponent {
}

describe('component: TestComponent', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [ FormsModule ],
      declarations: [TestComponent, NumberValidator]
    });
  });

  it('should validate (easy)', () => {
    expect(numberValidator(new FormControl('123'))).toEqual({
      'validateNumber': { 'valid': false }
    });
    expect(numberValidator(new FormControl('123456789'))).toEqual(null);
  });

  it('should validate (tedious)', async(() => {
    let fixture = TestBed.createComponent(TestComponent);
    let comp = fixture.componentInstance;
    let debug = fixture.debugElement;
    let input = debug.query(By.css('[name=number]'));

    fixture.detectChanges();
    fixture.whenStable().then(() => {
      input.nativeElement.value = '123';
      dispatchEvent(input.nativeElement, 'input');
      fixture.detectChanges();

      let form: NgForm = debug.children[0].injector.get(NgForm);
      let control = form.control.get('number');

      // just to show a few different ways we can check validity
      expect(control.hasError('validateNumber')).toBe(true);
      expect(control.valid).toBe(false);
      expect(form.control.valid).toEqual(false);
      expect(form.control.hasError('validateNumber', ['number'])).toEqual(true);

      input.nativeElement.value = '123456789';
      dispatchEvent(input.nativeElement, 'input');
      fixture.detectChanges();

      expect(form.control.valid).toEqual(true);
    });
  }));
});