<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<style type="text/css" media="all">
  #svgtest {
    font: 2.3cm "svgtest", fantasy;
  }
</style>
<defs>
  <font-face id="test" font-family="svgtest">
    <font-face-src>
      <font-face-name name="NOT A VALID FONT" />
      <font-face-name name="sdlfkj" />
      <font-face-name name="  sdflkjsdf " />
      <font-face-uri xlink:href="url(bogus)" />
      <font-face-uri xlink:href="#bogus" />
      <font-face-name name="Ahem" />
    </font-face-src>
  </font-face>
</defs>
<text id="svgtest" x="10" y="3cm">ONLY BLOCKS</text>
<text x="30" y="3cm">The text above should only show Ahem blocks</text>
</svg>