Question

我正在尝试在管道的单元测试中模拟服务。我面临的问题是，即使遵循多个指南并使用多种方法，我仍然会在执行测试时遇到import { TestBed } from '@angular/core/testing'; import { DatePipe } from './date.pipe'; import { DateFormat } from '@app/enums'; import { ApiService } from '@app/services'; import { MainService } from '@app/state'; class MockApiService extends ApiService { transformDateToApi(date: Date = new Date()): string { return '13-08-1996T22:10:32'; } } describe('DatePipe', () => { const testDate = new Date('13-08-1996T22:10:32'); const testDateAsString = '13-08-1996 22:10:32'; const pipe = new DatePipe(); let apiService: ApiService; beforeEach(() => { TestBed.configureTestingModule({ providers: [ { provide: ApiService, useClass: MockApiService }, { provide: MainService, useValue: {} } ] }); apiService = TestBed.get(ApiService); }); // Date object test it('date (as Date object) will be properly transformed in DateFormat.Xshort format', () => { expect(pipe.transform(testDate, DateFormat.Xshort)).toBe('13-08-\'96'); }); it('date (as Date object) will be properly transformed in DateFormat.Short format', () => { expect(pipe.transform(testDate, DateFormat.Short)).toBe('13-08-1996'); }); it('date (as Date object) will be properly transformed in DateFormat.Pretty format', () => { expect(pipe.transform(testDate, DateFormat.Pretty)).toBe('13 augustus 1996'); }); it('date (as Date object) will be properly transformed in DateFormat.WithTime format', () => { expect(pipe.transform(testDate, DateFormat.WithTime)).toBe('13 augustus 1996 22:10:32'); }); });错误。

我见过其他人在组件上执行此任务，但对于Pipe来说，它略有不同，对吗？

date.pipe.spec.ts

import { Pipe, PipeTransform } from '@angular/core';
import { ApiService } from '@app/services';
import { DateFormat } from '@app/enums';
import { DateSegments } from '@app/interfaces';

@Pipe({
    name: 'formatDate'
})
export class DatePipe implements PipeTransform {
    private date: DateSegments;

    constructor (
        private apiService: ApiService
    ) { }

    transform(date: Date | string, format: DateFormat = DateFormat.Pretty): string {
        if ( date instanceof Date ) {
            console.log(this.apiService);
            console.log(ApiService);
            date = this.apiService.transformDateToApi(date);
        }

..... (irrelevant code to this question)

date.pipe.ts

TypeError: Cannot read property 'transformDateToApi' of undefined

我收到的错误是items。

此时我的试错策略已被带回到将代码粉碎在一起，这个策略并没有教给我任何东西。

Answer 1

你做错了。

管道非常简单，不应该使用试验台来测试它们。相反，模拟您的服务，只需通过注入它来创建管道。像这样的东西。

import { TestBed } from '@angular/core/testing';
import { DatePipe } from './date.pipe';
import { DateFormat } from '@app/enums';
import { ApiService } from '@app/services';
import { MainService } from '@app/state';

const apiServiceMock = {
  transformDateToApi(date: Date = new Date()): string {
    return '13-08-1996T22:10:32';
  }
};

describe('DatePipe', () => {
  const testDate = new Date('13-08-1996T22:10:32');
  const testDateAsString = '13-08-1996 22:10:32';

  let pipe: DatePipe;
  let apiService: ApiService;

  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
        { provide: ApiService, useValue: apiServiceMock },
        { provide: MainService, useValue: {} }
      ]
    });
    apiService = TestBed.get(ApiService);
  });

  beforeEach(() => {
    pipe = new DatePipe(apiServiceMock as any);
  });

  // Date object test
  it('date (as Date object) will be properly transformed in DateFormat.Xshort format', () => {
    expect(pipe.transform(testDate, DateFormat.Xshort)).toBe('13-08-\'96');
  });
  it('date (as Date object) will be properly transformed in DateFormat.Short format', () => {
    expect(pipe.transform(testDate, DateFormat.Short)).toBe('13-08-1996');
  });
  it('date (as Date object) will be properly transformed in DateFormat.Pretty format', () => {
    expect(pipe.transform(testDate, DateFormat.Pretty)).toBe('13 augustus 1996');
  });
  it('date (as Date object) will be properly transformed in DateFormat.WithTime format', () => {
    expect(pipe.transform(testDate, DateFormat.WithTime)).toBe('13 augustus 1996 22:10:32');
  });
});

在管道单元测试中进行模拟时服务未定义

1 个答案: