chromium/src/third_party/blink/web_tests/virtual/text-antialias/international/bidi-control-chars-treated-as-ZWS.html

This tests that Unicode bidi control characters are not rendered and have zero width. The next two lines should look the same.
<div style="font-family: 'Times New Roman';">
    a&#x202d;e&#x300;<br>
    ae&#x300;
</div>