Vitest 5.0 ships with faster test runs and stricter defaults that can break existing suites

Teams upgrading should check their CI artifact paths, Node and Vite versions, and any plugins still pinned to Vitest 4.

VoidZero has shipped Vitest 5.0, a major release of its Vite-based testing framework that prioritises speed and tightens several defaults. Benchmarks reported by the team show gains of roughly 8 to 25 percent across most setups, with VM pool runs up to 53 percent faster, driven by shared Vite servers for inline projects, a stabilised on-disk module cache and fewer messages between the main process and workers. The release also adds a vitest doctor command that suggests faster configurations and a Trace View in Browser Mode for stepping through recorded interactions. Several defaults have become stricter: clearMocks is now on by default, unawaited async assertions fail instead of warning, and toThrow('') matches any error, which can turn passing Vitest 4 suites red in CI. Teams upgrading need Vite 6.4, Node.js 22.12 or newer, and a separately installed vite for Yarn users, and CI artifact paths must be updated because reports now sit under .vitest/. Some ecosystem plugins, such as Cloudflare's vitest-pool-workers, still pin their peer range to v4 and fail before any tests run.