Testing with Bun

1.txt

# Upgrade
$bun upgrade 
$bun -version
1.3.13

# Create a new project
$bun init demo  

✓ Select a project template: Blank

 + .gitignore
 + CLAUDE.md
 + .cursor/rules/use-bun-instead-of-node-vite-npm-pnpm.mdc -> CLAUDE.md
 + index.ts
 + tsconfig.json (for editor autocomplete)
 + README.md

To get started, run:

    bun run index.ts

bun install v1.3.13 (bf2e2cec)

+ @types/bun@1.3.12
+ typescript@5.9.3 (v6.0.3 available)

5 packages installed [2.91s]

2.txt

# Run tests with isolation (fresh global per file)
$bun test --isolate ./tests

# Run tests in parallel across all CPU cores
$bun test --parallel ./tests

# Run tests in parallel with 8 workers
$bun test --parallel=8 ./tests

# In a GitHub Actions matrix with 3 jobs:
$bun test --shard=1/3
$bun test --shard=2/3
$bun test --shard=3/3

3.txt

# Run tests affected by uncommitted changes (unstaged + staged + untracked)
$bun test --changed

# Run tests affected by changes since a specific commit, branch, or tag
$bun test --changed=HEAD~1
$bun test --changed=main

# Combine with --watch to re-filter on every restart
$bun test --changed --watch

web.test.ts

await using view = new Bun.WebView({ width: 1024, height: 600 });
await view.navigate("https://seleniumbase.io/coffee/");

await view.click("div[data-test='Espresso']");

var textCart = await view.evaluate(
  `document.querySelector("#app > ul > li:nth-child(2) > a").textContent`,
);
if (textCart !== "cart (1)") {
  throw new Error(`Expected text to be "cart (1)", but got "${textCart}"`);
}
const png = await view.screenshot({ format: "jpeg", quality: 90 });
await Bun.write("page.jpg", png);