编写 angular2 测试并更改模拟 return 值 - 使其变干？

Question

我正在为服务编写一些测试，并且正在更改模拟函数的响应以测试各种情况。目前，每次我想更改模拟的响应时，我都需要重置 TestBed 并再次配置测试模块，将我的新模拟作为依赖项注入。

我觉得一定有一种 DRYer 的方式来编写这个规范，但我想不出来。有人有什么想法吗？

（我知道我可以将此服务的测试编写为标准 ES6 class，但我的组件和服务使用来自 angular 的 Http 响应模拟内容时遇到了相同的情况.)

这是我的规范文件：

import { TestBed, inject } from '@angular/core/testing';
import { Observable } from 'rxjs/Observable';
import { UserService, RestService } from '../index';
import { User } from '../../../models/index';


let getUserSpy = jasmine.createSpy('getUser');
let upsertUserSpy = jasmine.createSpy('upsertUser');


// NOTE that initally, the MockRestService throws errors for all responses
class MockRestService {
  getUser = getUserSpy.and.returnValue(Observable.throw('no thanks'));
  upsertUser = upsertUserSpy.and.returnValue(Observable.throw('no thanks'));
}


describe('User service - ', () => {

  let service;

  /**
   * First TestBed configuration
   */
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
        UserService,
        {
          provide: RestService,
          useClass: MockRestService,
        }
      ]
    });
  });

  beforeEach(inject([UserService], (user: UserService) => {
    service = user;
  }));

  /* ... tests ... */

  describe('getUser/ upsertUser succeeds with INVALID user - ', () => {

    /**
     * Altering mock
     */
    class MockRestService {
      getUser = getUserSpy.and.returnValue(Observable.of({json: () => {
        return {name: 'dave'};
      }}));
      upsertUser = upsertUserSpy.and.returnValue(Observable.of({json: () => {}}));
    }

    /**
     * Reset and reconfigure TestBed. Lots of repetition!
     */
    beforeEach(() => {
      TestBed.resetTestingModule();
    });

    beforeEach(() => {
      TestBed.configureTestingModule({
        providers: [
          UserService,
          {
            provide: RestService,
            useClass: MockRestService,
          }
        ]
      });
    });

    beforeEach(inject([UserService], (user: UserService) => {
      service = user;
    }));

    /* ... tests ... */

  });

  describe('getUser/upsertUser succeeds with valid user', () => {
    const validResponse = {
      json: () => {
        return {
          firstName: 'dave',
          lastName: 'jones',
          email: 'dave@gmail.com'
        };
      }
    };

    /**
     * Altering mock
     */
    class MockRestService {
      getUser = getUserSpy.and.returnValue(Observable.of(validResponse));
      upsertUser = upsertUserSpy.and.returnValue(Observable.of(validResponse));
    }

    /**
     * Reset and reconfigure testbed. Lots of repetition!
     */
    beforeEach(() => {
      TestBed.resetTestingModule();
    });

    beforeEach(() => {
      TestBed.configureTestingModule({
        providers: [
          UserService,
          {
            provide: RestService,
            useClass: MockRestService,
          }
        ]
      });
    });

    beforeEach(inject([UserService], (user: UserService) => {
      service = user;
    }));

    /* ... tests ... */

  });

});

Answer 1

可能是

的一些变体

function setupUserTestbed() {
    beforeEach(() => {
      TestBed.configureTestingModule({...});
    });

    afterEach(() => {
      TestBed.resetTestingModule();
    });
 }

...
setupUserTestbed();
...
setupUserTestbed();

但是 describe 块的目的（除了在测试报告中对规格进行分组之外）是以最有效的方式排列 before* 和 after* 块。

如果顶级 describe 块有 beforeEach 块，您可以确定它会影响嵌套 describe 块中的规范。如果 describe 块是兄弟块，则应将常见行为移至顶层 describe。如果兄弟 describe 块没有顶级 describe，则应该创建它。

在发布的代码中，顶层 describe('User service - ', () => { ... }) 已经有 beforeEach 个块 TestBed.configureTestingModule、TestBed.resetTestingModule（应该在 afterEach 中执行）和 inject。无需在嵌套的 describe 块中复制它们。

MockRestService class 的配方与任何在规范之间交替的模拟相同。它应该是一个 let/var 变量：

describe(...
  let MockRestService = class MockRestService { ... };

  beforeEach(() => { Testbed... });

  describe(...
    MockRestService = class MockRestService { ... };

    beforeEach(inject(...));

这种模式可以有很多变化。 class 本身可能是常量，但 getUser 和 upsertUser 属性可能会交替：

let getUserSpy;
let upsertUserSpy;

class MockRestService {
  getUser = getUserSpy;
  ...
}

describe(...

  beforeEach(() => { Testbed... });

  beforeEach(() => {
    getUserSpy = jasmine.createSpy().and.returnValue(...);
    ...
  });

  describe(...
    beforeEach(() => {
      getUserSpy = jasmine.createSpy().and.returnValue(...);
      ...
    });

    beforeEach(inject(...));

这也解决了一个重要的问题，因为间谍在每个规范中都应该是新鲜的，即在 beforeEach 中定义。 getUserSpy 和 upsertUserSpy 可以在 Testbed 配置之后但在 inject 之前重新分配（这是 MockRestService class 可能实例化的地方）。 =41=]

编写 angular2 测试并更改模拟 return 值 - 使其变干？

Write angular2 tests and changing the mock return values - make it DRY?

angular

unit-testing

jasmine

angular2-testing