diff --git a/package.json b/package.json
index 6b04c04..92f8ffe 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,10 @@
     "random",
     "distribution"
   ],
+  "devDependencies": {
+    "mocha": "*",
+    "chai": "*"
+  },
   "author": "Eric Zhang",
   "license": "BSD",
   "readmeFilename": "README.md"