This test verified #document-fragment is displayed when showShadowRoot is enabled.

- <div id="container">
    - <div id="test1">
          #document-fragment
      </div>
    - <div id="test2">
          #document-fragment
          "only test"
      </div>
    - <div id="test3">
          #document-fragment
          "with "
          <span>elements</span>
      </div>
  </div>