message: refactor: improve test case
diff: @@ -4,18 +4,16 @@ import { invokeWithErrorHandling } from 'core/util/error'
  describe('invokeWithErrorHandling', () => {
  if (typeof Promise !== 'undefined') {
  it('should errorHandler call once when nested calls return rejected promise', done => {
  - let times = 0
  -
  - Vue.config.errorHandler = function () {
  - times++
  - }
  + const originalHandler = Vue.config.errorHandler
  + const handler = Vue.config.errorHandler = jasmine.createSpy()
  invokeWithErrorHandling(() => {
  return invokeWithErrorHandling(() => {
  return Promise.reject(new Error('fake error'))
  })
  }).then(() => {
  - expect(times).toBe(1)
  + Vue.config.errorHandler = originalHandler
  + expect(handler.calls.count()).toBe(1)
  done()
  })
  })
  