The best way yo update Copter code

I’m interested in modifying arducopter code. My intention is to use Eclipse to edit the code. But before upload the application to a real copter, first Ï want to test if everything is correct. So I’m planning to use SITL to simulate the new code and show some messages to inform about the execution of the new code. Do you think this is a good alternative? Can you tell me if there’s a better one?