Hide success messages when running in sauce

This should help debug the firefox issues that only occur when executing against sauce.

Gruntfile.js

@@ -132,7 +132,7 @@ module.exports = function(grunt) {
       all: {
         options: {
           build: process.env.TRAVIS_JOB_ID,
-          urls: ['http://localhost:9999/spec/'],
+          urls: ['http://localhost:9999/spec/?headless=true'],
           detailedError: true,
           concurrency: 2,
           browsers: [

spec/index.html

@@ -3,7 +3,21 @@
     <title>Mocha</title>
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
+
     <link rel="stylesheet" href="/node_modules/mocha/mocha.css" />
+    <style>
+      .headless .suite > h1,
+      .headless .test.pass {
+        display: none;
+      }
+    </style>
+
+    <script>
+      // Show only errors in "headless", non-interactive mode.
+      if (/headless=true/.test(location.href)) {
+        document.documentElement.className = 'headless';
+      }
+    </script>
     <script src="/node_modules/mocha/mocha.js"></script>
     <script>
       mocha.setup('bdd');