Angular 2 测试 karma 。具体要测试什么

Question

我正在尝试学习如何使用 karma-jasmine 为 angular 2( typescript 文件)创建测试。我的疑问是，要测试 component.ts 文件，我只能测试我在 HTML 文件中调用的方法，还是可以测试所有的方法？ 例如:我有这个模型文件 modal.nota.component.ts

    import { Component, Input, Output, EventEmitter } from '@angular/core';
    import { Nota } from './nota.model'


    @Component({
      moduleId: module.id,
      selector: 'modal-nota',
      templateUrl: 'modal.nota.component.html'
    })
    export class ModalNotaComponent {

      test : boolean = true;

      setFalse(test) {
        this.test = false;
        return test;
      }
  }

而且我没有在我的 HTML 文件中调用方法 'setFalse'，但我想测试他。如何调用和测试规范文件中的方法？ 模态.nota.spec.ts

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { By }              from '@angular/platform-browser';
import { DebugElement }    from '@angular/core';

import { ModalNotaComponent } from '../modal.nota.component';

describe('Test of test variable', () => {

  let component: ModalNotaComponent;
  let fixture: ComponentFixture<ModalNotaComponent>;
  beforeEach(() => {
    TestBed.compileComponents(); // ModalNotaComponent test instance
    TestBed.configureTestingModule({
      declarations: [ ModalNotaComponent ], // declare the test component
    });

    fixture = TestBed.createComponent(ModalNotaComponent);
    component = fixture.componentInstance;
  });


  it('Should show that the value of test variable is true', () => {
    expect(component.test).toBe(true);
  }); 

  it('Should test setFalse method', () => {
    let r = null;
    let t = true;  
    r = component.setFalse(t);
    expect(r).toBe(false);
  }); 

});

此测试无效。我收到这个错误 photo of the errors

Answer 1

经过一些搜索，我找到了如何从 component.ts 文件(服务、模态等)调用方法和变量。您所要做的就是在测试中实例化该类。这是新的测试文件:

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { By }              from '@angular/platform-browser';
import { DebugElement }    from '@angular/core';

import { ModalNotaComponent } from '../modal.nota.component';

describe('Test of test variable', () => {

  beforeEach(() => {

    this.modalNota = new ModalNotaComponent();
  });

  it('Should show that the value of test variable is true', () => {
    expect(this.modalNota.test).toBeTruthy()
  }); 

  it('Should test setFalse method', () => {
    let r = null;
    let t = true;  
    r = this.modalNota.setFalse(t);
    expect(r).toBeFalsy()
  }); 

});

致谢:Live chat Developers Blog - Testing Angular 2 apps Part 2: Dependency Injection and Components