If your api is wrong, and you have unit tests for that wrong api, and you have time to rewrite it the right way, you can write a set of methods with the correct

If your api is wrong, and you have unit tests for that wrong api, and you have time to rewrite it the right way, you can write a set of methods with the correct api which is a shim for the wrong api (you don't care about perf here), write your refactored version, and switch your now-tested shim to the correct api (and then probably keep it as a reference for the new way of doing things). If you find yourself doing this frequently though unit tests might not be ideal for your situation.