I explained that I follow a testing-first mindset wherever possible. For unit testing, I use Jest and React Testing Library to write meaningful tests that mimic user interactions rather than just testing implementation details. For more complex flows, I also include integration tests and occasionally use Playwright or Cypress for end-to-end testing. On the accessibility front, I make sure to use semantic HTML and accessible components. I validate forms with proper aria-* attributes, ensure keyboard navigation works smoothly, and run audits using tools like axe-core, Lighthouse, and eslint-plugin-jsx-a11y during development.