Assert First Development

A good programmer writes about 10 lines of code a day. Maybe less maybe more, though it's a very interresting topic leading to names like Barry Boehm and Tom DeMarco, it's not the subject of this post. I just wanted to point out that eventhough undoubtedly useful, IntelliSense, or any autocompletion tool for that matter, is way overrated. A programmer might type in that single line of code of the hour in five minutes, or in eight without IntelliSense. I'm glad we've got that out of the way. Next, if you are a TDDer and don't already use the Arrange/Act/Assert concept, start today and you will never look back. Anyways.

"Assert First Development"[1] is about writing the assert of your test first. This gives you the means to write the act-part in a way your assert needs it, and then the arrange-part as your act and assert needs it. This way you have to think about only one thing at a time. If you do it the other way around - that is from arrange to assert - you always have to think about all three parts simultaneously. You could of course say "I'm very smart and I can think about many things at once", and I believe you can, but you could use all your cleverness to solve one problem at a time, potentially solving things even better. If not, you still haven't lost anything, you just did your job sequentially. But chances are that your assert will be right the first time around, not mentioning your arrange in which you set really only those things up your act needs, and not the things you think your act will need. Only thing you lose is some parts of your IntelliSense, but we already established that it's really not that much of a loss.
One last thought. Assert First Development is another great example of the pull-system: there is never waste produced, we don't setup mocks or fakes or anything we might not need eventually.

References:
[1] Kent Beck: Test Driven Development: By Example