Finished tests in 9 months 12 days 6 hours, 1.0046 tests/month, 3.5037 assertions/month. As developers, we are proponents and practitioners of TDD. This means that we try to keep a good suite of tests for our Sybil application. This leads us notably to start decoupling it as much as possible. Once the test are in place, one of the important thing is to keep them fast. As founders of 8th color, we tend to follow the Customer Development and Lean Startup movement (is this the right word?), as the two go quite well together. One of the key aspects of both approaches is to not assume but rather test any assumptions you may have about your business, whether it is your market fit, problem fit or way to market.