升级到Angular / rxjs 6打破了Karma测试

Question

在我升级到Angular的新版本之后，我以前工作过的一个测试打破了，我不知道为什么。即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：Expected $._subscribe = Function to equal Function.。由于异步错误功能，测试是否失败？

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

如果你把测试重写为

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([{}]);
    });
});

此测试由于可观察性而失败，并且您的最终期望中的订阅应该解决此问题。