Bun Test

Sets up Bun's built-in test runner with Jest-compatible APIs, so you can write unit, integration, and snapshot tests without adding dependencies. The skill walks through creating test directories, configuring bunfig.toml, writing tests with describe/expect blocks, and setting up mocks and spies. Includes a Jest migration guide since the syntax is nearly identical (just swap imports from @jest/globals to bun:test). The 3-10x speed improvement over Jest is real and noticeable on larger test suites. Good for new Bun projects or migrating existing Jest setups. Covers the basics well, though the advanced mocking patterns require checking the reference docs.