don't rely on window scope in typingTest.js

www/_socket/typingTest.js

@@ -18,7 +18,7 @@ define(function () {
         };
     };
 
-    var testInput = function (el, offset, cb) {
+    var testInput = function (doc, el, offset, cb) {
         var i = 0,
             j = offset,
             input = " The quick red fox jumps over the lazy brown dog.",
@@ -43,7 +43,7 @@ define(function () {
 
                 console.error(err);
                 var next = document.createTextNode("");
-                window.inner.appendChild(next);
+                doc.appendChild(next);
                 el = next;
                 j = -1;
             }