Iwas Bornready (9/30/2015)
I develop code in a fashion similar to what you have stated. I also find that expectations change as we develop, especially when we start showing the results requested. What I struggle with is trying to create any sort of automated testing. I rarely do anything that is the same, otherwise I would just use what I already have. I do not have my own personal testing environment. It is shared with many others. So the data is ever changing. I can't seem to configure anything that is repeatable. The environment keeps changing.
You should look at a testing framework. The idea is the data is the same for tests. You need a consistent environment, which is part of the testing. Even when nothing is the same, you can have effects between modules, so having tests ensures the functionality you expect is still working.