third_party/web_platform_tests/fetch/nosniff/stylesheet.html

<!-- quirks mode is important, text/css is already required otherwise -->
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<div id=log></div>
<script>
  var fails = ["", "?type=", "?type=x", "?type=x/x"],
      passes = ["?type=text/css", "?type=text/css;blah"]

  fails.forEach(function(urlpart) {
    async_test(function(t) {
      var link = document.createElement("link")
      link.rel = "stylesheet"
      link.onerror = t.step_func_done(function(){})
      link.onload = t.unreached_func("Unexpected load event")
      link.href = "resources/css.py" + urlpart
      document.body.appendChild(link)
    }, "URL query: " + urlpart)
  })

  passes.forEach(function(urlpart) {
    async_test(function(t) {
      var link = document.createElement("link")
      link.rel = "stylesheet"
      link.onerror = t.unreached_func("Unexpected error event")
      link.onload = t.step_func_done(function(){
        if(passes[passes.length-1] == urlpart) {
          assert_equals(document.styleSheets.length, passes.length)
        }
      })
      link.href = "resources/css.py" + urlpart
      document.body.appendChild(link)
    }, "URL query: " + urlpart)
  })
</script>