that variable is required to suppress output when unit testing, also travis has composer preinstalled

.travis.yml

@@ -7,8 +7,7 @@ php:
   - hhvm
 
 before_script:
-  - curl -s http://getcomposer.org/installer | php
-  - php composer.phar install -n
+  - composer install -n
 
 script:
   - cd tst && ../vendor/bin/phpunit

tst/zerobin.php

@@ -145,7 +145,7 @@ class zerobinTest extends PHPUnit_Framework_TestCase
         file_put_contents(CONF, '');
         ob_start();
         new zerobin;
-        ob_get_contents();
+        $content = ob_get_contents();
     }
 
     /**