Testing, fixed prices and bug-free guarantees

After my lightning talk for NWDUG on automated testing with Drupal, the question was asked how to find time for testing.

I've written about whether you need to ask for permission to write tests (you don't), and if you need to estimate tasks, you include the time and effort for writing tests as part of the estimate.

As someone who only offers fixed prices for development work and covers all work with a bug-free guarantee, I want to provide well-written, stable and tested software to my customers so I'm not always fixing bugs for free.