diff --git a/io/io_test.html b/io/io_test.html
index a5413b8..0281f90 100644
--- a/io/io_test.html
+++ b/io/io_test.html
@@ -14,33 +14,33 @@
       setUp: function() {
         buffer = new bitjs.io.ByteBuffer(10);
       },
-      tests: [
-        function testWriteNumberThenRead() {
+      tests: {
+        testWriteNumberThenRead: function() {
           buffer.writeNumber(1234, 4);
           var stream = new bitjs.io.ByteStream(buffer.data);
           muther.assertEquals(1234, stream.peekNumber(4));
         },
-        function testWriteUnsignedByteThenRead() {
+        testWriteUnsignedByteThenRead: function() {
           buffer.writeNumber(192, 1);
           var stream = new bitjs.io.ByteStream(buffer.data);
           muther.assertEquals(192, stream.readNumber(1));
         },
-        function testWriteSignedByteThenRead() {
+        testWriteSignedByteThenRead: function() {
           buffer.writeSignedNumber(-120, 1);
           var stream = new bitjs.io.ByteStream(buffer.data);
           muther.assertEquals(-120, stream.readSignedNumber(1));
         },
-        function testWriteSignedPositiveNumberThenRead() {
+        testWriteSignedPositiveNumberThenRead: function() {
           buffer.writeSignedNumber(1234, 4);
           var stream = new bitjs.io.ByteStream(buffer.data);
           muther.assertEquals(1234, stream.readSignedNumber(4));
         },
-        function testWriteSignedNegativeNumberThenRead() {
+        testWriteSignedNegativeNumberThenRead: function() {
           buffer.writeSignedNumber(-128, 1);
           var stream = new bitjs.io.ByteStream(buffer.data);
           muther.assertEquals(-128, stream.readSignedNumber(1));
         },
-        function testWriteOverflowUnsigned() {
+        testWriteOverflowUnsigned: function() {
           var passed = false;
           try {
               buffer.writeNumber(256, 1);
@@ -49,7 +49,7 @@
           }
           muther.assert(passed);
         },
-        function testWriteOverflowSignedPositive() {
+        testWriteOverflowSignedPositive: function() {
           var passed = false;
           try {
               buffer.writeSignedNumber(128, 1);
@@ -58,7 +58,7 @@
           }
           muther.assert(passed);
         },
-        function testWriteOverflowSignedNegative() {
+        testWriteOverflowSignedNegative: function() {
           var passed = false;
           try {
               buffer.writeSignedNumber(-129, 1);
@@ -66,8 +66,8 @@
               passed = true;
           }
           muther.assert(passed);
-        }
-      ]
+        },
+      },
     });
 </script>
 </body>
diff --git a/muther.js b/muther.js
index 94684d1..83bed60 100644
--- a/muther.js
+++ b/muther.js
@@ -6,23 +6,35 @@
  */
 var muther = muther || {};
 
+var $ = function(s) { return document.querySelector(s) || {}; }
 muther.assert = function(cond, err) { if (!cond) { throw err; } };
 muther.assertEquals = function(a, b, err) { muther.assert(a === b, err); };
 
-muther.addResult_ = function(innerHTML, pass) {
-  document.body.innerHTML += '<div style="' +
-      (pass ? 'color:#090' : 'color:#900') + '">' + innerHTML + '</div>';
+muther.set_ = function(id, style, innerHTML) {
+  $('#' + id).innerHTML = '';
+  document.body.innerHTML += '<div id="' + id + '" style="' + style + '">' + innerHTML + '</div>';
 };
 
 muther.go = function(spec) {
-  var setup = spec['setUp'] || function(){};
-  var tearDown = spec['tearDown'] || function(){};
-  spec['tests'].forEach(function(test) {
-    try {
-      setup(); test(); tearDown();
-      muther.addResult_('PASS: ' + test.name, true);
-    } catch(e) {
-      muther.addResult_('FAIL: ' + test.name + ': ' + e, false);
+  Object.keys(spec['tests']).forEach(function(testName) {
+    var test = spec['tests'][testName];
+    if (test instanceof Promise) {
+      muther.set_(testName, 'color:#F90', 'RUNNING: ' + testName);
+      // TODO: What if we want setup() and tearDown()?
+      test.then(function() {
+        muther.set_(testName, 'color:#090', 'PASS: ' + testName);
+      }, function(err) {
+        muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err);
+      });
+    } else if (test instanceof Function) {
+      var setup = spec['setUp'] || function(){};
+      var tearDown = spec['tearDown'] || function(){};
+      try {
+        setup(); test(); tearDown();
+        muther.set_(testName, 'color:#090', 'PASS: ' + testName);
+      } catch (err) {
+        muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err);
+      }
     }
   });
 };