diff --git a/benchmark/code/actual-using-immutable.js b/benchmark/code/actual-using-immutable.js
new file mode 100644
index 0000000..43d9b01
--- /dev/null
+++ b/benchmark/code/actual-using-immutable.js
@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = require('../../index.js').immutable;
\ No newline at end of file
diff --git a/benchmark/code/actual-using.js b/benchmark/code/actual-using.js
new file mode 100644
index 0000000..a0a1615
--- /dev/null
+++ b/benchmark/code/actual-using.js
@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = require('../../index.js');
\ No newline at end of file
diff --git a/benchmark/code/while-hash-in.js b/benchmark/code/while-hash-in.js
new file mode 100644
index 0000000..e6129d8
--- /dev/null
+++ b/benchmark/code/while-hash-in.js
@@ -0,0 +1,16 @@
+'use strict';
+
+module.exports = function(arr) {
+  var i = arr.length;
+
+  var hash = Object.create(null);
+  var res = [];
+
+  while (i--) {
+    if (!(arr[i] in hash)) {
+      hash[arr[i]] = true;
+      res.push(arr[i]);
+    }
+  }
+  return res;
+};
diff --git a/benchmark/index.js b/benchmark/index.js
index bbcac44..beed47e 100644
--- a/benchmark/index.js
+++ b/benchmark/index.js
@@ -2,7 +2,7 @@
 
 var Suite = require('benchmarked');
 var suite = new Suite({
-  add: 'code/*.js',
+  code: 'code/*.js',
   fixtures: 'fixtures/*.js',
   cwd: __dirname
 });
diff --git a/package.json b/package.json
index d87640a..d2c217b 100644
--- a/package.json
+++ b/package.json
@@ -58,5 +58,8 @@
     "lint": {
       "reflinks": true
     }
+  },
+  "dependencies": {
+    "benchmarked": "^1.1.1"
   }
 }