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bun test decides which files to run as tests by matching their paths against a set of patterns.

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Default Discovery Logic

By default, bun test recursively searches the project directory for files that match these patterns:
  • *.test.{js|jsx|ts|tsx} - Files ending with .test.js, .test.jsx, .test.ts, or .test.tsx
  • *_test.{js|jsx|ts|tsx} - Files ending with _test.js, _test.jsx, _test.ts, or _test.tsx
  • *.spec.{js|jsx|ts|tsx} - Files ending with .spec.js, .spec.jsx, .spec.ts, or .spec.tsx
  • *_spec.{js|jsx|ts|tsx} - Files ending with _spec.js, _spec.jsx, _spec.ts, or _spec.tsx

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Exclusions

By default, bun test ignores:
  • node_modules directories
  • Hidden directories (those starting with a period .)
  • Files that don’t have JavaScript-like extensions (based on available loaders)

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Customizing Test Discovery

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Position Arguments as Filters

To filter which test files run, pass additional positional arguments to bun test:
terminal
bun test <filter> <filter> ...
Any test file with a path that contains one of the filters runs. Filters are substring matches, not glob patterns. For example, to run all tests in a utils directory:
terminal
bun test utils
This matches files like src/utils/string.test.ts and lib/utils/array_test.js.

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Specifying Exact File Paths

To run a specific file in the test runner, make sure the path starts with ./ or / to distinguish it from a filter name:
terminal
bun test ./test/specific-file.test.ts

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Filter by Test Name

To filter tests by name rather than file path, use the -t/--test-name-pattern flag with a regex pattern:
terminal
# run all tests with "addition" in the name
bun test --test-name-pattern addition
The pattern is matched against the test name prefixed with the labels of all its parent describe blocks, separated by spaces. For example, a test defined as:
https://mintcdn.com/bun-1dd33a4e/JUhaF6Mf68z_zHyy/icons/typescript.svg?fit=max&auto=format&n=JUhaF6Mf68z_zHyy&q=85&s=7ac549adaea8d5487d8fbd58cc3ea35bmath.test.ts
describe("Math", () => {
  describe("operations", () => {
    test("should add correctly", () => {
      // ...
    });
  });
});
This test is matched against the string “Math operations should add correctly”.

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Changing the Root Directory

By default, Bun looks for test files starting from the current working directory. Change this with the root option in bunfig.toml:
bunfig.toml
[test]
root = "src"  # Only scan for tests in the src directory

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Execution Order

Tests run in the following order:
  1. Test files run sequentially (not in parallel)
  2. Within each file, tests run sequentially in definition order