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

test/randomHexColorCode/randomHexColorCode.js

@@ -1,4 +1,4 @@
-module.exports = () => {
+module.exports = randomHexColorCode = () => {
 let n = ((Math.random() * 0xfffff) | 0).toString(16);
 return '#' + (n.length !== 6 ? ((Math.random() * 0xf) | 0).toString(16) + n : n);
 };