Nokia transitioned to a new mobile platform in 6 months and faced challenges validating mobile apps. They took an adaptive approach to quality assurance, using unit tests during prototyping, component tests during setup, and both automated and manual UI tests during execution. This approach provided minimum quality while allowing tests to focus on different levels from controls to the full app stack. Lessons included automating as much as possible, having testers and developers share environments, and estimating story impact during sprints.