title: Mocha with Vue: Resolution method is overspecified
body: <p>this is my test:</p>
  
  <pre><code>describe('Documentation Component', () =&gt; {
    it('renders a vue instance', (done) =&gt; {
      expect(shallow(Documentation).isVueInstance()).toBe(true)
      done()
    })
  
    it('Gets documentation', async (done) =&gt; {
      let wrapper = shallow(Documentation)
  
      await flushPromises()
      expect(wrapper.vm.$data.documentation).toBe('')
      done()
    })
  })
  </code></pre>
  
  <p>I followed the guide in the Vue.js docs and I can't get this to work. I need to wait for the docs promise:</p>
  
  <pre><code>mounted () {
      // --------------------------------------
      this.$http.get(Config.urls.documentation).then(
        (response) =&gt; {
          this.documentation = response.body
        },
        (errorResponse) =&gt; {
          EventBridge.$emit('request.error', errorResponse)
          this.documentation = ''
        }
      )
    }
  </code></pre>
  
  <p>The thing is, if I use the "done" function gives this error and without it, it gives this:</p>
  
  <pre><code>Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called;
  </code></pre>
  
  <p>I'm not sure what I need to do, just followed the docs. :(</p>