Bug fixes and tests for switches

lib/switches.js

@@ -8,7 +8,14 @@ module.exports = {
 
   innerHTML: function(oldEl, newEl) {
     oldEl.innerHTML = newEl.innerHTML
-    oldEl.className = newEl.className
+
+    if (newEl.className === "") {
+      oldEl.removeAttribute("class")
+    }
+    else {
+      oldEl.className = newEl.className
+    }
+
     this.onSwitch()
   },