angular - 升级到 Angular/rxjs 6 会破坏 Karma 测试

Question

在我升级到新版本的 Angular 之后，我以前的一个测试失败了，我不知道为什么。也就是说，我有一个记录错误的功能:

import { Observable, of } from 'rxjs';

export function handleError<T>(operation='operation', result?: T) {
  return (error: any): Observable<T> => {
    console.error(error);
    console.info(`${operation} failed: ${error.message}`);
    return of(result as T);
  }
}

我测试它:

it('#handleError return function should return an object', () => {
  let errorFunction = handleError('dummyFetch', [{}]);
  expect(typeof errorFunction({ message: 'Something went wrong.'})).toEqual('object');
  expect(errorFunction({ message: 'Something went wrong.'})).toEqual(of([{}]));
});

失败的行是 expect(errorFunction({ message: 'Something went wrong.'})).toEqual(of([{}])); 并报告错误:预期 $._subscribe = 函数等于函数。。会不会是异步错误函数导致测试失败？

编辑:这是我解决的解决方案:

it('#handleError return function should return an object', () => {
  let errorFunction = handleError('dummyFetch', [{}]);
  expect(typeof errorFunction({ message: 'Something went wrong.' })).toEqual('object');

  let error = errorFunction({ message: 'Something went wrong.' });
  error.subscribe(value => {
    expect(value).toEqual([{}]);
  });
});

Answer 1

如果您将测试重写为

it('#handleError return function should return an object', () => {
  let errorFunction = handleError('dummyFetch', [{}]);
  expect(typeof errorFunction({ message: 'Something went wrong.'})).toEqual('object');
  errorFunction.subscribe((result) => {
        expect(result).toEqual([{}]);
    });
});

此测试因可观察对象而失败，您最终期望中的订阅应该可以解决此问题。