Right but 2 often ends up being perfunctory whereas if you can test routinely against the local environment you’ll see a lot more and for example course correct

Right but 2 often ends up being perfunctory whereas if you can test routinely against the local environment you’ll see a lot more and for example course correct earlier. It depends on what you’d consider an iteration as well. I don’t think the loop is closed until you’ve seen your code running in situ. Unit tests might let you have more confidence that things will work at that point. Running in situ could also be integration testing FWIW. Depends on what it is you’re making.