I do like Go tests. Would love to have ability to find out untested parts of the code base though to increase coverage, but I do not think there is a way to measure this with available tools just yet.

Although I have yet to make integration tests that require live database and other dependencies. That will be fun...

Anyway, my main gripe with tests or TDD is that even if the code base is 95% finished, not talking libraries here, even small code changes can cause a cascade of changes that need to be addressed and tests essentially multiply the work load by a factor of 10, easy. And I am not talking about big changes. It might be a simple addition of a new struct field which suddenly breaks half of your test suite. Hence teste should be, in my experience, written as the absolutely last step before going live. Otherwise they might impose massive costs on time, and potentially money(if we're talking actual business and not one man shot type of project).