Testing

Bosia apps use bun test — Bun's built-in test runner. No extra config, no extra dependencies.

Running Tests

From your project root:

bun test

Common flags:

bun test --watch         # re-run on file change
bun test --coverage      # print coverage report
bun test --bail          # stop on first failure
bun test --timeout 10000 # per-test timeout in ms
bun test src/lib/foo.test.ts  # run a single file
bun test src/lib              # run a directory

Test File Naming

Bun automatically discovers files matching:

• *.test.ts / *.test.tsx
• *.test.js / *.test.jsx
• *.spec.ts / *.spec.tsx
• any file inside a __tests__/ folder

Place tests next to the code they cover, or under __tests__/. Both work.

src/
├── lib/
│   ├── utils.ts
│   ├── utils.test.ts        # next to source
│   └── __tests__/
│       └── helpers.test.ts  # in __tests__ folder

Writing a Test

Use test, expect, and the lifecycle hooks from bun:test:

import { test, expect, describe, beforeEach } from "bun:test";
import { slugify } from "./utils.ts";

describe("slugify", () => {
	test("lowercases and replaces spaces", () => {
		expect(slugify("Hello World")).toBe("hello-world");
	});

	test("strips punctuation", () => {
		expect(slugify("Hello, World!")).toBe("hello-world");
	});
});

Add Test Scripts

Add scripts to your package.json so bun run test works:

{
	"scripts": {
		"test": "bun test",
		"test:watch": "bun test --watch",
		"test:coverage": "bun test --coverage"
	}
}

Environment Variables in Tests

bun test does not auto-load Bosia's .env.test. Load it yourself with a setup file.

Create tests/setup.ts:

import { loadEnvFile } from "node:process";

try {
	loadEnvFile(".env.test");
} catch {
	// .env.test is optional
}

Tell Bun to run it before each test file by adding to bunfig.toml:

[test]
preload = ["./tests/setup.ts"]

Now any *.test.ts file sees variables from .env.test.

What to Test

Focus on pure logic that doesn't depend on the request lifecycle:

• Utility functions (formatters, validators, parsers)
• Server-side business logic extracted from load() / actions
• Component logic (state machines, derived values)

Bosia-specific helpers for testing load(), form actions, API routes, and full SSR rendering are on the roadmap but not yet shipped. For now, extract logic into plain functions and test those.

Watch Mode

bun test --watch re-runs affected tests on file save — useful while developing. It does not currently integrate with bosia dev; run them in separate terminals.