diff --git a/composer/bin/phpunit b/composer/bin/phpunit
index 1cfe331c16c..90e8deec7d4 100755
--- a/composer/bin/phpunit
+++ b/composer/bin/phpunit
@@ -36,7 +36,17 @@
  */
 define('PHPUnit_MAIN_METHOD', 'PHPUnit_TextUI_Command::main');
 
-// pull in vendor/autoload.php as defined by composer
-require __DIR__ .'/../../../../autoload.php';
+function includeIfExists($file)
+{
+    if (file_exists($file)) {
+        return include $file;
+    }
+}
+
+if ((!$loader = includeIfExists(__DIR__.'/../../vendor/autoload.php')) && (!$loader = includeIfExists(__DIR__.'/../../../../autoload.php'))) {
+    die('You must set up the project dependencies, run the following commands:'.PHP_EOL.
+        'curl -s http://getcomposer.org/installer | php'.PHP_EOL.
+        'php composer.phar install'.PHP_EOL);
+}
 
 PHPUnit_TextUI_Command::main();