title: What does react test-utils expect when it refers to ReactComponent tree?
body: <p>I'm trying to write tests for some d3 elements that are rendered via react component, and I was hoping to be able to pick out some of the svg elements on the page and check their width to see if they're behaving as expected.</p>
  
  <p>I'm not entirely sure what the react test-utils docs are expecting when they say ReactComponent tree.</p>
  
  <pre><code>array scryRenderedDOMComponentsWithClass(ReactComponent tree, string className)
  </code></pre>
  
  <p>I'm rendering my component into the document via:</p>
  
  <pre><code>  var component = TestUtils.renderIntoDocument(
      &lt;ProgressCircle percentage={75} /&gt;
    );
  </code></pre>
  
  <p>And I'm able to successfully check for a css className by doing:</p>
  
  <pre><code>  it('should render an element with the class "progress-circle"', function() {
      var circleContainer = TestUtils.findRenderedDOMComponentWithClass(component, 'progress-circle');
      expect(circleContainer).toBeDefined();
    });
  </code></pre>
  
  <p>But I don't understand what I need to provide to some of these find / scry methods that expect a ReactComponent tree.</p>
  
  <p><a href="http://facebook.github.io/react/docs/test-utils.html" rel="noreferrer">http://facebook.github.io/react/docs/test-utils.html</a></p>
  
  <p>Edit:</p>
  
  <p>For more clarification, the rendered DOM for this component looks like this:</p>
  
  <pre><code>&lt;div class="progress-circle"&gt;
    &lt;svg&gt;
      &lt;g&gt;
      &lt;/g&gt;
    &lt;/svg&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>... and I'm trying to find the  element.</p>