vfsStream is required for travis
diff --git a/composer.json b/composer.json
index 48aea9f..e21aaed 100644
--- a/composer.json
+++ b/composer.json
@@ -2,5 +2,8 @@
     "name" : "ellislab/codeigniter",
     "require": {
         "php": ">=5.2.4"
-    }
+    },
+    "require-dev": {
+      "mikey179/vfsStream": "*"
+		}
 }
\ No newline at end of file