Missed what seemed to be a critical update to the testem.js file 3.3

config/environment.js

@@ -134,6 +134,7 @@ module.exports = function(environment) {
     ENV.APP.LOG_VIEW_LOOKUPS = false;
 
     ENV.APP.rootElement = '#ember-testing';
+    ENV.APP.autoboot = false;
   }
 
   if (process.env.FINGERPRINT) {

testem.js

@@ -10,13 +10,15 @@ module.exports = {
   ],
   browser_args: {
     Chrome: {
-      mode: 'ci',
-      args: [
+      ci: [
         // --no-sandbox is needed when running Chrome inside a container
         process.env.TRAVIS ? '--no-sandbox' : null,
         '--disable-gpu',
         '--headless',
         '--no-sandbox',
+        '--disable-dev-shm-usage',
+        '--disable-software-rasterizer',
+        '--mute-audio',
         '--remote-debugging-port=9222',
         '--window-size=1440,900'
       ].filter(Boolean)

tests/index.html

@@ -11,6 +11,7 @@
     {{content-for "test-head"}}
 
     <link id = "vendor" rel="stylesheet" href="{{content-for 'baseAssets'}}assets/vendor.css">
+    <link id = "vendor" rel="stylesheet" href="{{content-for 'baseAssets'}}assets/ui.css">
     <link id="theme" rel="stylesheet">
     <link rel="stylesheet" href="{{content-for 'baseAssets'}}assets/test-support.css">
 
@@ -21,7 +22,7 @@
     {{content-for "body"}}
     {{content-for "test-body"}}
 
-    <script src="{{content-for 'baseAssets'}}testem.js" integrity=""></script>
+    <script src="/testem.js" integrity=""></script>
     <script src="{{content-for 'baseAssets'}}assets/vendor.js"></script>
     <script src="{{content-for 'baseAssets'}}assets/test-support.js"></script>
     <script src="{{content-for 'baseAssets'}}assets/ui.js"></script>