diff --git a/src/Composer/Repository/VcsRepository.php b/src/Composer/Repository/VcsRepository.php
index 481701d86..2d56efec6 100644
--- a/src/Composer/Repository/VcsRepository.php
+++ b/src/Composer/Repository/VcsRepository.php
@@ -13,31 +13,37 @@ class VcsRepository extends ArrayRepository
 {
     protected $url;
     protected $packageName;
+    protected $debug;
 
-    public function __construct(array $config)
+    public function __construct(array $config, array $drivers = null)
     {
         if (!filter_var($config['url'], FILTER_VALIDATE_URL)) {
             throw new \UnexpectedValueException('Invalid url given for PEAR repository: '.$config['url']);
         }
 
+        $this->drivers = $drivers ?: array(
+            'Composer\Repository\Vcs\GitHubDriver',
+            'Composer\Repository\Vcs\GitBitbucketDriver',
+            'Composer\Repository\Vcs\GitDriver',
+            'Composer\Repository\Vcs\HgBitbucketDriver',
+            'Composer\Repository\Vcs\HgDriver',
+        );
+
         $this->url = $config['url'];
     }
 
+    public function setDebug($debug)
+    {
+        $this->debug = $debug;
+    }
+
     protected function initialize()
     {
         parent::initialize();
 
-        $debug = false;
-
-        $drivers = array(
-            'Composer\Repository\Vcs\GitHubDriver',
-            'Composer\Repository\Vcs\GitBitbucketDriver',
-            'Composer\Repository\Vcs\GitDriver',
-            'Composer\Repository\Vcs\HgBitbucketDriver',
-            'Composer\Repository\Vcs\HgDriver',
-        );
+        $debug = $this->debug;
 
-        foreach ($drivers as $driver) {
+        foreach ($this->drivers as $driver) {
             if ($driver::supports($this->url)) {
                 $driver = new $driver($this->url);
                 $driver->initialize();