title: Jest Test - unique "key" prop error. Check the render method of xyz
body: <p>I have a jest test passing but getting the 'array or iterator should have a unique "key" prop.' errir</p>
  
  <p>I have found this is caused by a component not having a key prop defined but the component I am testing does.</p>
  
  <pre><code>            if (width) {
                  arrayList = listings.map(function (listing, i) {
                      return &lt;div className="col"&gt;&lt;ListingSimple key={i} listing={listing} displayType={displayType} /&gt;&lt;/div&gt;;
                  });
              }
              else {
                  arrayList = listings.map(function (listing, i) {
                      return &lt;ListingSimple key={i} listing={listing} displayType={displayType} /&gt;;
                  });
              }
  </code></pre>
  
  <p>In my test I have passed in all required props for the rest of the component. It is just giving the console.error for the above. arrayList is getting set properly and I can see my single or multiple list I am just having a blocker on this error.</p>
  
  <p>Just trying to removed this
  console.error...</p>
  
  <blockquote>
    <p>Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of... See fb react-warning-keys website for more information.</p>
  </blockquote>