使用 Jasmine Karma 测试分支

Question

我想知道如何在 Angular 中使用 Jasmin/Karma 测试分支。例如我有这个简单的功能：

  loadData(){
    if(this.faktor){ // here it should be true or false
      this.callMethod1();
    }else{
      this.callMethod2();
    }
  }

我需要增加测试覆盖率，并且需要测试分支。我尝试使用下面的示例，但它不起作用。我需要将 this.factor.isExist() 设置为 true。我该怎么做？

这是我的测试组件：

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { ChartComponent } from './chart.component';

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

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [ ChartComponent ]
    })
    .compileComponents();
  }));

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

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

  it('should call method1  if factor exist', () => {
    const spy =  spyOn(component, 'callMethod1');
    component.factor.isExist() as true;
    expect(spy).toHaveBeenCalled();
  })

  it('should call method2 if factor not exist', () =>{
    const spy =  spyOn(component, 'callMethod2');
    component.factor.isExist() as false;
    expect(spy).toHaveBeenCalled();
  })
});

Answer 1

代码覆盖率始终不可能达到 100%，但您的情况非常简单，您可以覆盖此处显示的所有代码。

it('should call method1  if factor exist', () => {
    const spy =  spyOn(component, 'callMethod1');
    component.factor = 'Your mock data goes here'
    component.loadData();       // should execute if part
    expect(spy).toHaveBeenCalled();
  })

  it('should call method2 if factor not exist', () =>{
    const spy =  spyOn(component, 'callMethod2');
    component.factor = null;    
    component.loadData();     // should execute else part
    expect(spy).toHaveBeenCalled();
  })