bun test

import { expect, test } from "bun:test";

test("2 + 2", () => {
  expect(2 + 2).toBe(4);
});

bun test <filter> <filter> ...

# run all tests or test suites with "addition" in the name
bun test --test-name-pattern addition

bun test ./test/specific-file.test.ts

jobs:
  build:
    name: build-app
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Install bun
        uses: oven-sh/setup-bun@v2
      - name: Install dependencies # (assuming your project has dependencies)
        run: bun install # You can use npm/yarn/pnpm instead if you prefer
      - name: Run tests
        run: bun test

bun test --reporter=junit --reporter-outfile=./bun.xml

# default value is 5000
bun test --timeout 20

bun test --concurrent

# Limit to 4 concurrent tests
bun test --concurrent --max-concurrency 4

# Default: 20
bun test --concurrent

import { test, expect } from "bun:test";

// These tests run in parallel with each other
test.concurrent("concurrent test 1", async () => {
  await fetch("/api/endpoint1");
  expect(true).toBe(true);
});

test.concurrent("concurrent test 2", async () => {
  await fetch("/api/endpoint2");
  expect(true).toBe(true);
});

// This test runs sequentially
test("sequential test", () => {
  expect(1 + 1).toBe(2);
});

import { test, expect } from "bun:test";

let sharedState = 0;

// These tests must run in order
test.serial("first serial test", () => {
  sharedState = 1;
  expect(sharedState).toBe(1);
});

test.serial("second serial test", () => {
  // Depends on the previous test
  expect(sharedState).toBe(1);
  sharedState = 2;
});

// This test can run concurrently if --concurrent is enabled
test("independent test", () => {
  expect(true).toBe(true);
});

// Chaining test qualifiers
test.failing.each([1, 2, 3])("chained qualifiers %d", input => {
  expect(input).toBe(0); // This test is expected to fail for each input
});

bun test --rerun-each 100

bun test --randomize

bun test --randomize

# Reproduce a previous randomized run
bun test --seed 123456

# bail after 1 failure
bun test --bail

# bail after 10 failure
bun test --bail=10

bun test --watch

bun test --preload ./setup.ts

import { test, expect, mock } from "bun:test";
const random = mock(() => Math.random());

test("random", () => {
  const val = random();
  expect(val).toBeGreaterThan(0);
  expect(random).toHaveBeenCalled();
  expect(random).toHaveBeenCalledTimes(1);
});

import { test, expect, mock } from "bun:test"; 
import { test, expect, jest } from "bun:test"; 

const random = mock(() => Math.random()); 
const random = jest.fn(() => Math.random()); 

// example usage of toMatchSnapshot
import { test, expect } from "bun:test";

test("snapshot", () => {
  expect({ a: 1 }).toMatchSnapshot();
});

bun test --update-snapshots

# Example: Enable quiet output for Claude Code
CLAUDECODE=1 bun test

# Still shows failures and summary, but hides verbose passing test output

bun test

bun test foo bar

bun test --test-name-pattern baz