diff --git a/package.json b/package.json
index 5ed3d0f..3ac22c5 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,8 @@
   ],
   "scripts": {
     "start": "node shadowtools.js",
-    "test": "node --test"
+    "test": "node --test",
+    "prepublishOnly": "npm test"
   },
   "keywords": [
     "outline",