diff --git a/package.json b/package.json
index de82230..fc19050 100644
--- a/package.json
+++ b/package.json
@@ -88,6 +88,7 @@
   },
   "license": "MIT",
   "devDependencies": {
+    "chai": "^3.3.0",
     "mocha": "^2.3.3"
   }
 }