generate new test that did already exist & update all module snippets with declaration

test/median/median.js

@@ -1,4 +1,4 @@
-module.exports = arr => {
+module.exports = median = arr => {
 const mid = Math.floor(arr.length / 2),
 nums = [...arr].sort((a, b) => a - b);
 return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2;