title: jest enzyme simulate('click') with event object and value
body: <p>I have a problem when I try to pass via simulate, event object with values.
  I am getting error:</p>
  
  <pre><code>TypeError: Cannot read property 'value' of null
  
    at SingleSymbol.handleLotChange.event [as handleLotChange] (src/containers/SingleSymbol.js:95:46)
    at onClick (src/containers/SingleSymbol.js:145:40)
    at node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:332:27
  </code></pre>
  
  <p>I have seen <a href="https://stackoverflow.com/questions/43921183/passing-an-event-object-to-enzyme-simulate">case</a> however I need to pass entire event object created as follows:</p>
  
  <pre><code>const event = new Event('click', {"target":{"value":8}})
  </code></pre>
  
  <p>because in the function handling the 'click' event I am using stopPropagation function</p>
  
  <pre><code>handleLotChange = (event) =&gt; {
      event.stopPropagation()
      this.setState({lotValue: event.target.value})
    }
  </code></pre>
  
  <p>fragment of tested component:</p>
  
  <pre><code>(...)
            &lt;Grid item xs={4}  &gt;
              &lt;TextField
                label="Lot"
                id="lot-value"
                value={this.state.lotValue}
                onChange={(event) =&gt; this.handleLotChange(event)}
                onClick={(event) =&gt; this.handleLotChange(event)}
                type="number"
                className={classes.lotGrid}
                InputLabelProps={{
                  shrink: true,
                }}
                inputProps={{ min: "0", max: "10", step: "0.01" }}
              /&gt;
            &lt;/Grid&gt;
  (...)
  </code></pre>
  
  <p>test itself:</p>
  
  <pre><code>  it('captures inserted Lot value', () =&gt; {
      const event = new Event('click', {"target":{"value":8}})
      const wrapper = shallow(&lt;SingleSymbol data={dummy} classes={styles(theme)} /&gt;)
      wrapper.find('WithStyles(Paper)').simulate('click')
      wrapper.find('#lot-value').simulate('click', event)
      console.log(wrapper.state())
    })
  </code></pre>