The TDD Tetrahedron

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Are you looking for some concrete expression for Test Driven Development? Let me give you a glimpse of what I am working currently on – the TDD Tetrahedron.

The idea originates from when a colleague at Crisp, David Barnholdt, wrote about not focusing on one step at the time. So I thought for a while and came up with this idea, a tetrahedron where each side displayed “failing test”, “implementation” and “refactor”, respectively.

You turn it and look at the first side where you read “failing test”. You write a failing test and turn it again, reading “implementation”. Write the implementation and run the test to get the green bar. Once again you turn the tetrahedron and read “refactor”. You look for something to refactor, confident that if you do, you will be supported by unit tests all the way.

Or the thing just sit on your table to tell everyone how cool you are as being a TDD programmer. At least wish to be. 🙂

Anyways, here are some sneak preview pictures of the greatest thing that ever happened to the world of programming, ta da – the TDD Tetrahedron!

TDD TetrahedronTDD TetrahedronTDD Tetrahedron


  • 1
    2010-02-17 - 11:03 | Permalink

    Nice idea. How do I get one???

  • 2
    2010-02-19 - 10:24 | Permalink

    We are currently working on the problem of producing these in a cost-effective way. Suggestions are welcomed, make it in wood, plastic or paper? Which would be the most cost-effective?

    When solved, this will be announced here and on the front page of

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