QUnit tests should be run in random order.

lib/tasks/qunit.rake

@@ -47,7 +47,7 @@ task "qunit:test", [:timeout, :qunit_path] => :environment do |_, args|
     test_path = "#{Rails.root}/vendor/assets/javascripts"
     qunit_path = args[:qunit_path] || "/qunit"
     cmd = "node #{test_path}/run-qunit.js http://localhost:#{port}#{qunit_path}"
-    options = {}
+    options = { seed: Random.new.seed }
 
     %w{module filter qunit_skip_core qunit_single_plugin}.each do |arg|
       options[arg] = ENV[arg.upcase] if ENV[arg.upcase].present?