Test Driven Development proves useful at Google

This is a live blogging session from the recent Developer Testing Conference. The lecture was about Developer Testing in Google and this is only part of it:

"9:28 Standard Google practices include unit tests and functional tests, continuous builds, last known good build, release brances with authorized bug fix check-ins, focused teams for release engineering, production engineering and QA, bug tracking and logging of production runs.

9:30 Google brings in XP consultants to educate engineers, employs extreme feedback mechanisms like monitors and ambient orbs for visual feedback. They have specialized test and analysis tools during production and prior to production. Sometimes, they have fix-it weeks for fixing bugs, writing tests, improving documentation, etc.

9:32 When Google introduced XP to improve quality and other metrics, they hired a team of XP consultants and paired consultants with engineers. They created short projects for the employees with testing/XP as a theme. The teams focused on understanding code base and building good unit tests, and other TDD aspects. How to use infrastructure such as JUnit. XP was introduced at Google about 8 months ago. Engineers are not forced to use XP, but XP adoption is going well. Already, they have seen improvements in key metrics and in stability.

9:37 First steps were to build functional tests for existing code, develop tests that fail for bugs in the bugs database, unit tests for existing servlet handlers, unit tests and TDD for new code, and fix-it weeks devoted to developing unit tests and functional tests.

9:40 current status: very stable builds due to unit tests, better stability in backwards compatibility due to unit and functional tests. More TDD in future, with many more tests. Goal is to get to a stage where XP and testing offers benefits beyond build stability and backwards compatibility--much more quality in production software. "

[via TestDriven.Com]