Bun Jest Migration

Migrating from Jest to Bun's test runner is mostly painless since Bun maintains Jest compatibility, but there are a few gotchas around module mocking and timers. This guide walks you through removing Jest dependencies, updating imports from @jest/globals to bun:test, and translating the parts that differ (like jest.mock becoming mock.module and jest.fn becoming mock). The configuration section showing jest.config.js to bunfig.toml conversion is helpful, and the troubleshooting table catches the main pain points like mock hoisting not working the same way. If you're moving a test suite to Bun, this covers the practical stuff you'll actually hit.