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Spyon IsDevMode()在Angular 6+单元测试中?

karma-jasmine jasmine unit-testing angular

1

Jeremy Moritz Igal S. · 技术社区 · 8 年前

我的代码包括 if 像这样阻挡

服务:

import { isDevMode } from '@angular/core';

export class MyService {
  constructor() {}

  methodToTest(): {
    if (!isDevMode()) {
      doSomething();
    } else {
      doSomethingDifferentInDevMode();
    }
  }
}

my-service.spec.ts(仅限相关行):

it('should run doSomething() when isDevMode() returns false', () => {
  // what should i do here to mock a false value return for isDevMode() ?
  expect(doSomething).toHaveBeenCalled();
});

我怎么监视 isDevMode() 为了让它在这个单角度单位测试中返回错误,我可以测试它 doSomething() 是否被调用?

2 回复 | 直到 8 年前

1

3

Jeremy Moritz Igal S. 8 年前

首先将此函数包装到服务中:

import { isDevMode, Injectable } from '@angular/core';

@Injectable({ providedIn: 'root' })
export class DevModeService {
  constructor() {}

  isDevMode() {
    return isDevMode();
  }
}

然后,您可以在任何需要的地方注入此服务,就像处理任何其他服务一样:

import { DevModeService } from 'dev-mode.service';

export class MyService {
  constructor(private devModeService: DevModeService) {}

  methodToTest(): {
    if (!this.devModeService.isDevMode()) {
      doSomething();
    } else {
      doSomethingElse();
    }
  }
}

然后您可以在测试myservice时监视devmodeservice,就像处理任何其他依赖项一样:

it('should do something when in dev mode') {
  const devModeService: DevModeService = TestBed.get(DevModeService);
  spyOn(devModeService, 'isDevMode').and.returnValue(true);

  const myService: MyService = TestBed.get(MyService);
  myService.methodToTest();
  // ...
}

it('should do something else when in prod mode') {
  const devModeService: DevModeService = TestBed.get(DevModeService);
  spyOn(devModeService, 'isDevMode').and.returnValue(false);

  const myService: MyService = TestBed.get(MyService);
  myService.methodToTest();
  // ...
}

2

0

robrich 8 年前

答案似乎在评论中。谢谢@jbinzet。

// dev-mode-service.ts

import { isDevMode } from '@angular/core';

export class DevModeService {
  constructor() {}

  isDevMode(): {
    return isDevMode();
  }
}


// MyService.ts

import { isDevMode } from 'dev-mode-service';

export class MyService {
  constructor() {}

  methodToTest(): {
    if (!isDevMode()) {
      doSomething();
    } else {
      doSomethingDifferentInDevMode();
    }
  }
}