Add test class I forgot earlier.

tests/test_app/TestApp/Command/Helper/CommandHelper.php

@@ -0,0 +1,12 @@
+<?php
+namespace TestApp\Command\Helper;
+
+use Cake\Console\Helper;
+
+class CommandHelper extends Helper
+{
+    public function output($args)
+    {
+        $this->_io->out('I am helping ' . implode(' ', $args));
+    }
+}