You can't at first, but you don't need to. You just write normal code, with regular unit tests. Once you are satisfy, you can start playing with optimization and see if things break or get faster.
Things like monkey patching and stack inspection are the excetion rather than the rule. You may very well be able to safely disable many feature at some local level, or in prod but not dev, etc.
One of the event workers for Django monkey patches ‘socket’. A colleague and I discovered that an hour into debugging why something was misbehaving when we switched workers.
Things like monkey patching and stack inspection are the excetion rather than the rule. You may very well be able to safely disable many feature at some local level, or in prod but not dev, etc.