diff --git a/tests/muther.js b/tests/muther.js
index bd26706..9b90423 100644
--- a/tests/muther.js
+++ b/tests/muther.js
@@ -5,46 +5,46 @@
  *
  * Copyright(c) 2014, Google Inc.
  */
-var muther = {};
+var muther = {
+  assert(cond, err) { if (!cond) { throw err; } },
+  assertEquals(a, b, err) { muther.assert(a === b, err); },
+  assertThrows(fn, err) {
+    let threw = false;
+    try { fn(); } catch (e) { threw = true; }
+    muther.assert(threw, err);
+  },
 
-muther.assert = function(cond, err) { if (!cond) { throw err; } };
-muther.assertEquals = function(a, b, err) { muther.assert(a === b, err); };
-muther.assertThrows = function(fn, err) {
-  let threw = false;
-  try { fn(); } catch (e) { threw = true; }
-  muther.assert(threw, err);
-};
-
-muther.$ = function(id) {
-  let el = document.querySelector('#' + id);
-  if (!el) {
-    el = document.createElement('div');
-    el.id = id;
-    document.body.appendChild(el);
-  }
-  return el;
-};
-
-muther.set_ = function(id, style, innerHTML) {
-  muther.$(id).setAttribute('style', style);
-  muther.$(id).innerHTML = innerHTML;
-};
-
-muther.go = function(spec) {
-  let prevResult = Promise.resolve(true);
-  for (let testName in spec['tests']) {
-    muther.set_(testName, 'color:#F90', 'RUNNING: ' + testName);
-    try {
-      prevResult = prevResult.then(() => {
-        if (spec['setUp']) spec['setUp']();
-        const thisResult = spec['tests'][testName]() || Promise.resolve(true);
-        return thisResult.then(() => {
-          if (spec['tearDown']) spec['tearDown']();
-          muther.set_(testName, 'color:#090', 'PASS: ' + testName);
-        });
-      }).catch(err => muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err));
-    } catch (err) {
-      muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err);
+  $(id) {
+    let el = document.querySelector('#' + id);
+    if (!el) {
+      el = document.createElement('div');
+      el.id = id;
+      document.body.appendChild(el);
     }
-  }
+    return el;
+  },
+
+  set_(id, style, innerHTML) {
+    muther.$(id).setAttribute('style', style);
+    muther.$(id).innerHTML = innerHTML;
+  },
+
+  go(spec) {
+    let prevResult = Promise.resolve(true);
+    for (let testName in spec['tests']) {
+      muther.set_(testName, 'color:#F90', 'RUNNING: ' + testName);
+      try {
+        prevResult = prevResult.then(() => {
+          if (spec['setUp']) spec['setUp']();
+          const thisResult = spec['tests'][testName]() || Promise.resolve(true);
+          return thisResult.then(() => {
+            if (spec['tearDown']) spec['tearDown']();
+            muther.set_(testName, 'color:#090', 'PASS: ' + testName);
+          });
+        }).catch(err => muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err));
+      } catch (err) {
+        muther.set_(testName, 'color:#900', 'FAIL: ' + testName + ': ' + err);
+      }
+    }
+  },  
 };