bun-test

Run all test files found in the project

$ bun test

$ bun test [path/to/file.test.ts]

$ bun test --watch

$ bun test --coverage

bun test [paths...] [options]

--bail
    Exit on first test failure


--coverage
    Collect and report code coverage


--exact
    Disable test name minimization in reports


--filter <regex>
    Run tests matching filter regex


--grep <regex>
    Run tests whose names match grep regex


--reporter <name>
    Use reporter: list, tap, junit, json, etc.


--retries <num>
    Retry failed tests this many times


--run-in-band
    Run serially, not in parallel


--test-name-pattern <regex>
    Run tests matching name pattern regex


--test-timeout <ms>
    Timeout individual tests after ms


--throw-on-missing-coverage
    Fail if coverage thresholds unmet


--update-snapshots
    Update snapshot files


--version
    Print bun-test version


--watch
    Watch files for changes and re-run

bun test is the built-in test runner for Bun, an all-in-one fast JavaScript runtime, bundler, and package manager. It offers a zero-config, Jest- and Vitest-compatible API for writing unit and integration tests, supporting assertions via expect, test suites with describe and it, hooks like beforeEach, mocking, snapshots, and async testing.

Key advantages include blazing-fast execution (often 10-100x faster than Node.js/Jest due to Bun's Zig-based runtime and JIT), automatic test discovery (files matching *.test.{js,ts,jsx,tsx}, *.spec.{js,ts,jsx,tsx}, or directories named __tests__), parallel execution across cores, and built-in coverage with --coverage using istanbul-compatible reports.

It integrates seamlessly with bun install for dependencies, supports TypeScript out-of-the-box without transpilation, and provides reporters like list (default), tap, junit, and json. Watch mode enables rapid development feedback, and filtering options allow targeted runs. Ideal for modern JS/TS projects seeking simplicity and speed without external test frameworks.

Requires Bun installed (≥1.0); Node.js/Jest projects need API migration. No native ESM mocking quirks. Coverage requires bun-types for TS accuracy.

Auto-runs files: *.test.{js,ts,jsx,tsx}, *.spec.{js,ts,jsx,tsx}, tests/**/*.{js,ts}. Use bun --bun test to force Bun runtime.

Uses bunfig.toml or package.json "bun" section for custom reporters, patterns, timeouts.

Introduced in Bun 0.5.0 (Sep 2023) by Jarred Sumner; rapidly matured with Jest API parity by 1.0 (2024). Focuses on speed via Bun's libuv-free runtime.

bun(1), node(1), jest(1)