babelify only test files

lib/babel.js

@@ -2,10 +2,16 @@
 
 var resolveFrom = require('resolve-from');
 
+var options = {
+	only: /(test|test\-.+|test\/.+)\.js$/
+};
+
 try {
-	require(resolveFrom('.', 'babel-core/register') || resolveFrom('.', 'babel/register'));
+	var localBabel = resolveFrom('.', 'babel-core/register') || resolveFrom('.', 'babel/register');
+
+	require(localBabel)(options);
 } catch (err) {
-	require('babel-core/register');
+	require('babel-core/register')(options);
 }
 
 var path = process.argv[2];