Swift - How do you test whether a label has been updated when a button is tapped
<p>I've go a very simple calculator and I' trying to test whether a label gets updated when a button is tapped.</p>

<p>My test method looks like this:</p>

<pre><code>let app = XCUIApplication()
app.buttons["9"].tap()
</code></pre>

<p>I can visually see the Label being updated but I'm not sure how to test it.</p>

<p>I think I need to use <code>XCUIElementQuery</code> API to query label and then assert that the label text has changed. I'm just not sure how to do that.</p>

<p>I'm not sure about the following questions:</p>

<blockquote>
  <ul>
  <li>Do I need to know what the value is for the label to be able to query?</li>
  <li>Is there a way of querying for the label without knowing what the value is when the application starts?</li>
  </ul>
</blockquote>