测试组件,这取决于路由参数

Question

我有一个关于在an​​gular2中测试路由组件的问题.

这是一个简单的组件,它取决于带参数的路由'foo'.foo组件中的属性将设置为参数的值.

import {Component, OnInit} from '@angular/core';
import {ActivatedRoute, Params} from '@angular/router';

@Component({
    selector: 'my-component',
    templateUrl: './my-component.html'
})
export class MyComponent implements OnInit
{
    foo: string;

    constructor(
        private route: ActivatedRoute
    )
    {
    }

    ngOnInit()
    {
        this.route.params.subscribe((params: Params) => {
            this.foo = params['foo'];
        });
    }
}

现在我想测试一下,如果使用路径创建组件,则将正确设置param.所以我想要的地方expect(component.foo).toBe('3');.

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

import {Observable} from 'rxjs';

import {MyComponent} from './MyComponent';

describe('MyComponent', () => {
    let mockParams, mockActivatedRoute;

    let component: MyComponent;
    let fixture: ComponentFixture<MyComponent>;
    let debugElement: DebugElement;
    let element: HTMLElement;

    beforeEach(async(() => {
        mockParams = Observable.of<Params>({foo: '3'});
        mockActivatedRoute = {params: mockParams};

        TestBed.configureTestingModule({
            declarations: [
                MyComponent
            ],
            providers: [
                {provide: ActivatedRoute, useValue: mockActivatedRoute}
            ]
        }).compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(MyComponent);
        component = fixture.componentInstance;

        debugElement = fixture.debugElement;
        element = debugElement.nativeElement;

        fixture.detectChanges();
    });

    it('should set foo to "3"', () => {
        expect(component.foo).toBe('3');
    });
});

我的问题是我不知道如何等待,直到路线的解决完成,我可以做expect().在这个例子中,测试失败了,它说"预期未定义为'3'.".

有谁可以帮助我吗？!

谢谢!

Answer 1

好的,在angular2测试文档中读了一下,我看到了他们的ActivatedRouteStub课程.我创建了这个存根类,并用这个新类替换了我的原始模拟.现在它正在工作(识别mockActivatedRoute.testParams = {foo: '3'};第二个beforeEach中的行).

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

import {Observable} from 'rxjs';

import {MyComponent} from './MyComponent';

import { BehaviorSubject } from 'rxjs/BehaviorSubject';

@Injectable()
export class ActivatedRouteStub
{
    private subject = new BehaviorSubject(this.testParams);
    params = this.subject.asObservable();

    private _testParams: {};
    get testParams() { return this._testParams; }
    set testParams(params: {}) {
        this._testParams = params;
        this.subject.next(params);
    }
}

describe('MyComponent', () => {
    let mockParams, mockActivatedRoute;

    let component: MyComponent;
    let fixture: ComponentFixture<MyComponent>;
    let debugElement: DebugElement;
    let element: HTMLElement;

    beforeEach(async(() => {
        mockActivatedRoute = new ActivatedRouteStub();

        TestBed.configureTestingModule({
            declarations: [
                MyComponent
            ],
            providers: [
                {provide: ActivatedRoute, useValue: mockActivatedRoute}
            ]
        }).compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(MyComponent);
        component = fixture.componentInstance;

        debugElement = fixture.debugElement;
        element = debugElement.nativeElement;

        mockActivatedRoute.testParams = {foo: '3'};

        fixture.detectChanges();
    });

    it('should set foo to "3"', () => {
        expect(component.foo).toBe('3');
    });
});

你认为这是正确的方法吗？