bun-types
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Type definitions and documentation for Bun, an incredibly fast JavaScript runtime
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name: Write browser DOM tests with Bun and happy-dom
You can write and run browser tests with Bun's test runner in conjunction with [Happy DOM](https://github.com/capricorn86/happy-dom). Happy DOM implements mocked versions of browser APIs like `document` and `location`.
To get started, install `happy-dom`.
```sh
$ bun add -d @happy-dom/global-registrator
```
This module exports a "registrator" that injects the mocked browser APIs to the global scope.
```ts#happydom.ts
import { GlobalRegistrator } from "@happy-dom/global-registrator";
GlobalRegistrator.register();
```
We need to make sure this file is executed before any of our test files. That's a job for Bun's built-in [_preload_]() functionality. Create a `bunfig.toml` file in the root of your project (if it doesn't already exist) and add the following lines.
The `./happydom.ts` file should contain the registration code above.
```toml#bunfig.toml
[test]
preload = "./happydom.ts"
```
Now running `bun test` inside our project will automatically execute `happydom.ts` first. We can start writing tests that use browser APIs.
```ts
import { test, expect } from "bun:test";
test("set button text", () => {
document.body.innerHTML = `<button>My button</button>`;
const button = document.querySelector("button");
expect(button?.innerText).toEqual("My button");
});
```
With Happy DOM properly configured, this test runs as expected.
```sh
$ bun test
dom.test.ts:
✓ set button text [0.82ms]
1 pass
0 fail
1 expect() calls
Ran 1 tests across 1 files. 1 total [125.00ms]
```
Refer to the [Happy DOM repo](https://github.com/capricorn86/happy-dom) and [Docs > Test runner > DOM](https://bun.sh/docs/test/dom) for complete documentation on writing browser tests with Bun.