diff --git a/bin/cli.js b/bin/cli.js
index 033bf36..3670344 100644
--- a/bin/cli.js
+++ b/bin/cli.js
@@ -7,6 +7,7 @@ var fs = require('fs');
 
 if (!fsname || '--help' === fs || '-h' === fs) {
   console.error('Usage: hexdump.js <filepath>');
+  process.exit(2);
   return;
 }
 
@@ -14,6 +15,7 @@ try {
   fs.statSync(fsname);
 } catch(e) {
   console.error(e.message);
+  process.exit(3);
   return;
 }
 
diff --git a/package.json b/package.json
index c47ca93..628c2aa 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "description": "Like hexdump on *nix, but in JavaScript.",
   "main": "hexdump.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "node bin/cli.js hexdump.js"
   },
   "repository": {
     "type": "git",