使用 @Input() 进行 Angular2 单元测试

Question

我有一个在实例变量上使用 @Input() 注释的组件，我正在尝试为 openProductPage() 编写单元测试方法，但我对如何设置单元测试有点迷茫。我可以公开该实例变量，但我认为我不必诉诸于此。

如何设置我的 Jasmine 测试以便注入(inject)模拟产品(提供？)并且我可以测试 openProductPage() 方法？

我的组件:

import {Component, Input} from "angular2/core";
import {Router} from "angular2/router";

import {Product} from "../models/Product";

@Component({
    selector: "product-thumbnail",
    templateUrl: "app/components/product-thumbnail/product-thumbnail.html"
})

export class ProductThumbnail {
    @Input() private product: Product;


    constructor(private router: Router) {
    }

    public openProductPage() {
        let id: string = this.product.id;
        this.router.navigate([“ProductPage”, {id: id}]);
    }
}

Answer 1

这是来自官方文档https://angular.io/docs/ts/latest/guide/testing.html#!#component-fixture .因此，您可以创建新的输入对象 expectedHero 并将其传递给组件 comp.hero = expectedHero

还要确保最后调用 fixture.detectChanges();，否则属性将不会绑定(bind)到组件。

工作示例

// async beforeEach
beforeEach( async(() => {
    TestBed.configureTestingModule({
        declarations: [ DashboardHeroComponent ],
    })
    .compileComponents(); // compile template and css
}));

// synchronous beforeEach
beforeEach(() => {
    fixture = TestBed.createComponent(DashboardHeroComponent);
    comp    = fixture.componentInstance;
    heroEl  = fixture.debugElement.query(By.css('.hero')); // find hero element

    // pretend that it was wired to something that supplied a hero
    expectedHero = new Hero(42, 'Test Name');
    comp.hero = expectedHero;
    fixture.detectChanges(); // trigger initial data binding
});