TDD - Rewriting 3 million lines of code
Andreas Frömer, Head of Software Development at Finanztip, successfully used TDD to rewrite a legacy application consisting of 3 million lines of code. Key lessons include starting with system level tests to avoid regression bugs and using feature flags to replace old code while retaining system behavior. The approach emphasizes starting with system level tests before moving to component tests and applying TDD for both rewriting and refactoring.
