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

test/lowercaseKeys/lowercaseKeys.js

@@ -1,4 +1,4 @@
-module.exports = obj =>
+module.exports = lowercaseKeys = obj =>
 Object.keys(obj).reduce((acc, key) => {
 acc[key.toLowerCase()] = obj[key];
 return acc;