需求 You are given strings of different lengths. If the number of vowels (aeiou) are more than 30% of the string length then insert ‘mommy’ for each continuous set of vowels. 要求 使用TDD方式实现上述需求，注意TDD Cycle（红-绿-重构） YAGNI 小步提交 TIPS：注意测试用例的完整性