用 Jasmine 在 Angular 中模拟环境

Question

我仍在学习如何使用 Karma/Jasmine 编写角度测试。我想为环境的 isDebugMode 返回 false。当我更改它的代码时，它显然有效，但是我如何为此编写测试？我已经设置了一些测试，试图找出如何模拟环境。但似乎没有一个像我认为的那样工作。我想知道是否有人可以解释为什么这些会返回他们所做的值。

import { TestBed, inject } from '@angular/core/testing';
import { LoggerService } from './logger.service';
import { environment } from '../environments/environment';
import { mockEnvironment} from '../environments/environment.mock';

describe('Test', () => {

  beforeEach(() => {

    spyOn(console, 'error');
    spyOn(console, 'warn');

    TestBed.configureTestingModule({
      providers: [ LoggerService ]
    });


  });

  it('should be created',
    inject([LoggerService],
      (service: LoggerService) => {
        expect(service).toBeTruthy();
      }));

  it('should always work', function() {
    expect(true).toBe(true);
  });

  it('is the mocked environment returning false', function() {
    spyOn(mockEnvironment, 'isDebugMode');
    expect(mockEnvironment.isDebugMode).toEqual(false);
  });

  it('is the environment returning true', function() {
    spyOn(environment, 'isDebugMode');
    expect(environment.isDebugMode).toEqual(true);
  });

  it('enclosing in function makes everything true, why?',
    function () {
    spyOn(environment, 'isDebugMode').and.returnValue(false);
    inject([LoggerService],
      (service: LoggerService) => {
        const type = 'warn';
        const message = 'This message';
        service.log(type, message);

        expect(console.warn).not.toHaveBeenCalled(); // this does not seem to matter
      });
     }
  );
  it('enclosing in function makes everything true, why?',
    function () {
      spyOn(environment, 'isDebugMode').and.returnValue(false);
      inject([LoggerService],
        (service: LoggerService) => {
          const type = 'warn';
          const message = 'This message';
          service.log(type, message);

          expect(console.warn).toHaveBeenCalled(); // this does not seem to matter
        });
    }
  );
  it('should show up if isDebugMode is true',
    inject([LoggerService],
      (service: LoggerService) => {
        const type = 'warn';
        const message = 'This message';

        service.log(type, message);
        expect(console.warn).toHaveBeenCalled(); // this works
      })
  );
  it('should not show up if isDebugMode is false using spy with return value',
      inject([LoggerService],
        (service: LoggerService) => {
          const type = 'warn';
          const message = 'This message';
          spyOn(environment, 'isDebugMode').and.returnValue(false);

          service.log(type, message);
          expect(console.warn).not.toHaveBeenCalled(); // this is does not work
        })
  );
  it('should not show up if isDebugMode is false using spy with callfake',
    inject([LoggerService],
      (service: LoggerService) => {
        const type = 'warn';
        const message = 'This message';
        spyOn(environment, 'isDebugMode').and.callFake(mockEnvironment.isDebugMode); // boolean is not a function

        service.log(type, message);
        expect(console.warn).not.toHaveBeenCalled(); // this is does not work
      })
  );
  it('should not show up if isDebugMode is false using spy with stub',
    inject([LoggerService],
      (service: LoggerService) => {
        const type = 'warn';
        const message = 'This message';
        spyOn(environment, 'isDebugMode').and.stub();

        service.log(type, message);
        expect(console.warn).not.toHaveBeenCalled(); // this is does not work
      })
  );


});

这些是我要测试的文件：logger.service.ts

import { Injectable } from '@angular/core';
import { environment } from '../environments/environment';

const isDebugMode = environment.isDebugMode;

@Injectable()
export class LoggerService {

  log(type: string, message?: any): void {
    if (type === 'info' || type === 'warn' || type === 'debug' || type === 'error' || type === 'log') {
      const logFn: Function = (console)[type];
      if (isDebugMode) {
        logFn.apply(console, [message]);
      }
    } else {
      console.error('Logger type incorrect');
    }
  }
}

随着环境.ts

export const environment = {
  production: false,
  hmr: false,
  isDebugMode: true
};

和 environment.mock.ts

export const MockEnvironment = {
  production: false,
  hmr: false,
  isDebugMode: false
};

测试

• 应该创建 - 通过
• 应该总是工作 - 通过
• 模拟环境是否返回 false - 失败
• 环境是否返回 true - 失败
• 包含在函数中使一切成为真实，为什么？- 经过
• 包含在函数中使一切成为真实，为什么？- 经过
• 如果 isDebugMode 为真，应该显示 - 通过
• 如果使用带有返回值的 spy 为 false，则不应显示 isDebugMode - 失败
• 如果使用带有 callfake 的 spy 的 isDebugMode 为 false，则不应显示 - 失败
• 如果 isDebugMode 为 false，则不应显示使用带有存根的 spy - 失败