Assert that an element contains a descendant element with element with the given data-test-id attribute.

var element = createElement(`
  <section>
    <h1>Numbers</h1>
    <hr>
    <ol data-test-id="numbers">
      <li>One</li>
      <li>Two</li>
      <li>Three</li>
    </ol>
  </section>
`);
 
expect(element, 'to contain test id', 'numbers');

You get the following error when it fails:

expect(element, 'to contain test id', 'emojies');

expected
<section>
  
<h1>Numbers</h1>
  
<hr>
  
<ol data-test-id="numbers">
  
<li>...</li>
  
<li>...</li>
  
<li>...</li>
</ol>
</section>
to contain test id 'emojies'
  
expected DOMElement to contain elements matching '[data-test-id="emojies"]'

Using the not flag, you can assert that the test id shouldn't be found on any descendant elements:

expect(element, 'not to contain test id', 'emojies');

You get the following error when it fails:

expect(element, 'not to contain test id', 'numbers');

expected
<section>
  
<h1>Numbers</h1>
  
<hr>
  
<ol data-test-id="numbers">
  
<li>...</li>
  
<li>...</li>
  
<li>...</li>
</ol>
</section>
not to contain test id 'numbers'
  
expected DOMElement not to contain elements matching '[data-test-id="numbers"]'
 
NodeList[
  
<ol data-test-id="numbers">
  
<li>...</li>
  
<li>...</li>
  
<li>...</li>
</ol> // should be removed
]