angular2测试，我如何模拟子组件

问题描述

如何在茉莉花测试中模拟子组件？

How do I mock sub component in jasmine tests?

我有 MyComponent ，它使用 MyNavbarComponent 和 MyToolbarComponent

import {Component} from 'angular2/core';
import {MyNavbarComponent} from './my-navbar.component';
import {MyToolbarComponent} from './my-toolbar.component';

@Component({
  selector: 'my-app',
  template: `
    <my-toolbar></my-toolbar>
    {{foo}}
    <my-navbar></my-navbar>
  `,
  directives: [MyNavbarComponent, MyToolbarComponent]
})
export class MyComponent {}

当我测试这个组件时，我不想加载和测试那些两个子组件; MyNavbarComponent，MyToolbarComponent，所以我想模仿它。

When I test this component, I do not want to load and test those two sub components; MyNavbarComponent, MyToolbarComponent, so I want to mock it.

我知道如何使用提供模拟服务（MyService，useClass（...） ），但我不知道如何模拟指令;组件;

I know how to mock with services using provide(MyService, useClass(...)), but I have no idea how to mock directives; components;

  beforeEach(() => {
    setBaseTestProviders(
      TEST_BROWSER_PLATFORM_PROVIDERS,
      TEST_BROWSER_APPLICATION_PROVIDERS
    );

    //TODO: want to mock unnecessary directives for this component test
    // which are MyNavbarComponent and MyToolbarComponent
  })

  it('should bind to {{foo}}', injectAsync([TestComponentBuilder], (tcb) => {
    return tcb.createAsync(MyComponent).then((fixture) => {
      let DOM = fixture.nativeElement;
      let myComponent = fixture.componentInstance;
      myComponent.foo = 'FOO';
      fixture.detectChanges();
      expect(DOM.innerHTML).toMatch('FOO');
    });
  });

这是我的plunker示例;

Here is my plunker example;

推荐答案

作为请求我发布了另一个关于如何使用输入模拟子组件的答案 / 输出：

As requested, I'm posting another answer about how to mock sub components with input/output:

所以让我们首先说我们有 TaskListComponent 显示任务，并在每次点击其中一个时刷新：

So Lets start by saying we have TaskListComponent that displays tasks, and refreshes whenever one of them is clicked:

<div id="task-list">
  <div *ngFor="let task of (tasks$ | async)">
    <app-task [task]="task" (click)="refresh()"></app-task>
  </div>
</div>

app-task 是一个子组件 [任务] 输入和（点击）输出。

app-task is a sub component with the [task] input and the (click) output.

好的，现在我们想为我的 TaskListComponent 编写测试，当然我们不想测试真正的 app-task component。

Ok great, now we want to write tests for my TaskListComponent and of course we don't want to test the real app-taskcomponent.

所以@Klas建议我们可以配置我们的 TestModule ：

so as @Klas suggested we can configure our TestModule with:

schemas: [CUSTOM_ELEMENTS_SCHEMA]

我们可能在构建或运行时都没有出现任何错误，但除了子组件的存在外，我们将无法测试更多错误。

We might not get any errors at either build or runtime, but we won't be able to test much other than the existence of the sub component.

那么我们如何模拟子组件？

首先我们将为子组件（相同的选择器）定义一个模拟指令：

First we'll define a mock directive for our sub component (same selector):

@Directive({
  selector: 'app-task'
})
class MockTaskDirective {
  @Input('task')
  public task: ITask;
  @Output('click')
  public clickEmitter = new EventEmitter<void>();
}

现在我们将在测试模块中声明它：

Now we'll declare it in the testing module:

let fixture : ComponentFixture<TaskListComponent>;
let cmp : TaskListComponent;

beforeEach(() => {
  TestBed.configureTestingModule({
    declarations: [TaskListComponent, **MockTaskDirective**],
    // schemas: [CUSTOM_ELEMENTS_SCHEMA],
    providers: [
      {
        provide: TasksService,
        useClass: MockService
      }
    ]
  });

  fixture = TestBed.createComponent(TaskListComponent);
  **fixture.autoDetectChanges();**
  cmp = fixture.componentInstance;
});

• 请注意，因为灯具的子组件的生成是异步发生的在创建之后，我们激活其autoDetectChanges功能。



在我们的测试中，我们现在可以查询指令，访问其DebugElement的注入器，并通过它获取我们的模拟指令实例：

In our tests, we can now query for the directive, access its DebugElement's injector, and get our mock directive instance through it:

import { By } from '@angular/platform-browser';
const mockTaskEl = fixture.debugElement.query(By.directive(MockTaskDirective));
const mockTaskCmp = mockTaskEl.injector.get(MockTaskDirective) as MockTaskDirective;

[此部分通常应位于 beforeEach 部分，更清洁的代码。]

[This part should usually be in the beforeEach section, for cleaner code.]

从这里开始，测试是小菜一碟：）

From here, the tests are a piece of cake :)

it('should contain task component', ()=> {
  // Arrange.
  const mockTaskEl = fixture.debugElement.query(By.directive(MockTaskDirective));

  // Assert.
  expect(mockTaskEl).toBeTruthy();
});

it('should pass down task object', ()=>{
  // Arrange.
  const mockTaskEl = fixture.debugElement.query(By.directive(MockTaskDirective));
  const mockTaskCmp = mockTaskEl.injector.get(MockTaskDirective) as MockTaskDirective;

  // Assert.
  expect(mockTaskCmp.task).toBeTruthy();
  expect(mockTaskCmp.task.name).toBe('1');
});

it('should refresh when task is clicked', ()=> {
  // Arrange
  spyOn(cmp, 'refresh');
  const mockTaskEl = fixture.debugElement.query(By.directive(MockTaskDirective));
  const mockTaskCmp = mockTaskEl.injector.get(MockTaskDirective) as MockTaskDirective;

  // Act.
  mockTaskCmp.clickEmitter.emit();

  // Assert.
  expect(cmp.refresh).toHaveBeenCalled();
});

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