Vitest

Vitest 5 adds features like typescript build mode, pluggable benchmark providers, dom snapshot trace views, and merged reports for non-sharded multi-environment runs, alongside performance work and long-standing bug fixes. This is a breaking release: it now requires Node.js 22 and Vite 6.4, removes the sequential test/suite options and deprecated entry points, changes default output directories for attachments, reporters, and screenshots to .vitest paths, clears mocks by default before each test, and now fails tests when async assertions aren't awaited or expect.poll doesn't resolve in time, so projects must update configs, Node/Vite versions, and any code relying on old defaults or removed APIs.

Matters for: Teams running large Vitest suites with browser mode, benchmarking, or multi-environment sharded test runs across CI pipelines.