从头开始

Ideally,we would like to start at the beginning.

要是有可能,我从头开始。

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，否你得重新做所有的测试。反之，如果你有堆乱七八糟的代码同时还有很多测试的话，情况样了。