bun test

Run tests with Bun’s fast, Jest-compatible test runner

Bun ships with a fast, built-in, Jest-compatible test runner. Tests are executed with the Bun runtime, and support TypeScript and JSX out of the box.

$ bun test

Watch mode

Run tests in watch mode to automatically re-run tests when files change:

$ bun test --watch

Test file discovery

Bun automatically discovers test files based on naming conventions:

• Files with .test.ts, .test.tsx, .test.js, or .test.jsx extensions
• Files with _test.ts, _test.tsx, _test.js, or _test.jsx extensions
• Files in __tests__ directories

# Run all test files
$ bun test

# Run specific test file
$ bun test path/to/file.test.ts

# Run tests matching a pattern
$ bun test --test-name-pattern "should handle"

Command-line flags

Test execution

--timeout · number · default: "5000"

Set the per-test timeout in milliseconds

$ bun test --timeout 10000

--bail · number · default: "unlimited"

Exit the test suite after N failures. If you do not specify a number, it defaults to 1.

$ bun test --bail
$ bun test --bail 3

--rerun-each · number

Re-run each test file N times. Useful for catching flaky tests.

$ bun test --rerun-each 10

--only · boolean

Only run tests marked with .only()

$ bun test --only

--todo · boolean

Include tests marked with .todo()

$ bun test --todo

--concurrent · boolean

Run tests concurrently by default

$ bun test --concurrent

Test filtering

--test-name-pattern · string

Filter tests by name using a regular expression

$ bun test --test-name-pattern "auth"

Output & reporting

--reporter · string · default: "default"

Select a test reporter. Options: default, dot, junit, only-failures

$ bun test --reporter dot
$ bun test --reporter junit --reporter-outfile junit.xml

--reporter-outfile · string

Write reporter output to a file (for junit reporter)

$ bun test --reporter junit --reporter-outfile report.xml

Coverage

--coverage · boolean

Generate code coverage report

$ bun test --coverage

--coverage-reporter · string · default: "text"

Coverage output format. Options: text, lcov. Can specify multiple.

$ bun test --coverage --coverage-reporter text
$ bun test --coverage --coverage-reporter lcov --coverage-reporter text

--coverage-dir · string · default: "./coverage"

Directory to write coverage reports

$ bun test --coverage --coverage-dir my-coverage

See Code Coverage for more details.

Snapshots

--update-snapshots · boolean

Update snapshots instead of comparing them

$ bun test --update-snapshots

See Snapshot Testing for more details.

Exit codes

The bun test command will exit with:

• 0 if all tests pass
• 1 if any test fails
• 1 if no tests are found

Configuration

Test runner behavior can be configured in bunfig.toml:

[test]
# Set default timeout
timeout = 10000

# Coverage settings
coverageSkipTestFiles = true
coveragePathIgnorePatterns = ["node_modules", "*.config.ts"]

# Pre-load modules before running tests
preload = ["./setup.ts"]

# Set concurrency
concurrent = true

See Test Configuration for all available options.

Related

• Writing Tests
• Lifecycle Hooks
• Mocks
• Snapshots