If you have no tests and cruddy code, then you should probably throw it away and start again because you'll have to do all the testing, as opposed to if you have cruddy code with many tests.
果你有一堆乱七八糟代码且又没有测试,那么你最好是扔掉它们从头开始,否则你就得重新做所有测试。反,果你有一堆乱七八糟代码同时还有很多测试话,情况就不一样了。