On Sun, Feb 27, 2011 at 2:12 PM, Schwab,Wilhelm K <
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Understood. But, doing it correctly, how much of your time do you spend on the test writing/maintenance side?
None. Seriously none. I never pause and say "OK now it's time to write tests and maintain existing ones". It's part of the TDD cycle: write a test, make it green, refactor. write a test, make it green, refactor. The cycle can go from 1mn to 10mn, rarely more. And if you use the Pomodoro technique, you feel it even better. Test writing/maintenance is part of programming.
Sometimes you can say "OK before implementing this new story, I would like to refactor here and here (tests + code) because I don't like it". We also do this stuff on legacy code when tests are not here. But it's far easier when we have good test coverage.
I found some blog posts, but I was hoping for some peer-reviewed papers that go on the record.
I am trying to make the point you are making, and it will go over better if I can point to literature and some numbers that I suspect will be seen as sobering. Tests ARE being "written after" in this case, but assuming they change to a proper process, they still need to understand that tests take thought and work.
When tests are written after, it's another kind of story. Then "how much time we should spend writing test" is valid. I don't have any answer.
TDD is not easy. Learning to write good tests takes time (years), investment. If someone in your team have good experience with it, he should pair program continuously with other programmers. Participating in coding-dojo , code retreats with experienced developers is great too.
Laurent.
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On Sun, Feb 27, 2011 at 4:52 AM, Schwab,Wilhelm K <<mailto:
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Hello all,
Can anyone recommend a good reference on the amount of time one should expect to spend writing tests? I will have to be the messenger (will be wearing running shoes just in case...), but I want the message to come from a solid source.
If you develop the TDD way (which I always do at work) then I would say this question is not valid. Your production code will be there because of tests. In legacy system, new and refactored code will be there because of tests.
IMHO the questions "how much time should I spend writing tests?" or "how many tests should I write ?" are raised when tests are written after. And sadly tests often become a burden in this case and doesn't support the pressure of releases / last minute changes / ... (I've done it this way almost 10 years ago, not good :)
In TDD the question is "which stories / scenarios do we have to implement ?". It's more a Product owner / customer point of view.
The best book on TDD I've read is Dave Astels TDD: a practical guide (Indeed, this one has really changed my mind on how testing should be done, and other books I've read since don't).
Laurent
Bill