svoid test_findHTMLTagWithClassDeep() {
  S html = [[<div class="blu bla blo"><p class="bla"></p><p /></div><div class="what blablu"></div>]];
  assertEqualsVerbose(
    ll(
      [[<div class="blu bla blo"><p class="bla"></p><p /></div>]],
      [[<p class="bla"></p>]]
    ),
    lmap join(findHTMLTagWithClassDeep("bla", htmlTok(html))));
}