I found an interesting information about Unit testing on MethodsandTools.com
This poll examined how organizations perform unit testing. Is it an informal activity that is done before integration if there is some time left after programming or is it the key element of the development effort? The question was: How is unit testing performed at your location?
|Unit testing is not performed||17%||13%|
|Unit testing is informal||40%||46%|
|Unit tests cases are documented||9%||11%|
|Unit tests cases and their executions are documented||14%||16%|
|We use a Test Driven Development approach||20%||14%|
Participants: 384 (2006:460) / Ending date: October 2008 (February 2006)
The complete text and the guess why these results are as they are you find here.