diff --git a/map.js b/map.js
new file mode 100644
index 0000000..775d7ac
--- /dev/null
+++ b/map.js
@@ -0,0 +1,6 @@
+const {basename} = require('path')
+const map = base =>
+  base === 'index.js' ? 'index.js'
+  : base === 'cmd.js' ? 'bin/cmd.js'
+  : `lib/${base}`
+module.exports = test => map(basename(test))