Airbnb successfully migrated nearly 3,500 React component test files from Enzyme to React Testing Library (RTL) in just six weeks by leveraging large language models (LLMs) and automation.This approach significantly reduced the estimated manual effort of 1.5 years.The migration process involved breaking down tasks into per-file steps, implementing retry loops with dynamic prompts, and providing additional context to handle complex files.This strategy ensured the preservation of test intent and code coverage throughout the transition.