React 19 Test Migration Patterns Reference for all test file migrations required by React 19. Priority Order Fix test files in this order; each layer depends on the previous: 1. import fix first, it unblocks everything else 2. → fix immediately after act 3. Full react-dom/test-utils cleanup remove remaining imports 4. StrictMode call counts measure actual, don't guess 5. Async act wrapping for remaining "not wrapped in act" warnings 6. Custom render helper verify once per codebase, not per test --- 1. act() Import Fix If mixed with other test-utils imports: --- 2. Simulate → fireEvent --- 3.…