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.
如果你有一堆乱七八糟的代码且又没有测试,那么你最好是扔掉它从头开始,否则你就得重所有的测试。反之,如果你有一堆乱七八糟的代码同时还有很多测试的话,情况就不一样了。