LayoutTests/fast/css/shadow-viewport-units.html

<style>
#a { text-shadow: 0px 0px 0vh black; } /* Should be valid - we support viewport units in shadow */
</style>
<div id="a"></div>
<script>
window.addEventListener("load", function () {
    if (window.testRunner)
        testRunner.dumpAsText();

    var a = document.getElementById("a");
    var output = document.createElement("p");
    document.body.appendChild(output);
    if (window.getComputedStyle(a).textShadow == "none")
        output.innerText = "FAIL: No shadow style";
    else
        output.innerText = "PASS: Shadow style: " + window.getComputedStyle(a).textShadow;
}, false);
</script>