### Database setup example with globalSetup

Source: https://rstest.rs/config/test/global-setup

Example of a global setup file that connects to MongoDB, seeds test data, and cleans up in teardown, along with the corresponding rstest.config.ts that references it.

```TypeScript
// db-setup.ts
let dbConnection: any;

export async function setup() {
  const { MongoClient } = await import('mongodb');
  const client = new MongoClient(process.env.TEST_MONGODB_URI!);
  await client.connect();

  dbConnection = client.db('test');

  // Seed test data
  await dbConnection.collection('users').insertMany([
    { name: 'John', email: '[email protected]' },
    { name: 'Jane', email: '[email protected]' },
  ]);

  console.log('✓ Database connected and seeded');
}

export async function teardown() {
  if (dbConnection) {
    await dbConnection.dropDatabase();
    await dbConnection.client.close();
    console.log('✓ Database cleaned up');
  }
}
```

```TypeScript
import { defineConfig } from '@rstest/core';

export default defineConfig({
  globalSetup: ['./db-setup.ts'],
  include: ['**/*.test.ts'],
});
```

--------------------------------

### Configure setupFiles in rstest.config.ts

Source: https://rstest.rs/config/test/setup-files

Use this configuration to specify setup modules that run before each test file. The example sets setupFiles to ['./scripts/rstest.setup.ts'].

```TypeScript
import { defineConfig } from '@rstest/core';

export default defineConfig({
  setupFiles: ['./scripts/rstest.setup.ts'],
});
```

--------------------------------

### rs.mock: Setup file for unmock example

Source: https://rstest.rs/api/runtime-api/rstest/mock-modules

This setup file (rstest.setup.ts) registers a mock for './src/sum' using rs.mock, which returns a sum function that adds 100 to the result. This mock is executed in setupFiles and is later cancelled by rs.unmock in the test file.

```typescript
import { rs } from '@rstest/core'
;
rs.mock('./src/sum', () => {
  return {
    sum: (a: number, b: number) => a + b + 100,
  };
});
```

--------------------------------

### Install dependencies with bun

Source: https://rstest.rs/guide/framework/react

Installs the same dependencies using bun.

```bash
bun add @rstest/core @rsbuild/plugin-react @testing-library/react @testing-library/jest-dom happy-dom -D
```

--------------------------------

### Install @rstest/adapter-rslib with deno

Source: https://rstest.rs/integration/rslib/

Install the adapter as a dev dependency using deno.

```bash
deno add npm:@rstest/adapter-rslib -D
```

--------------------------------

### global-setup.ts: Start and stop HTTP server for remote

Source: https://rstest.rs/guide/advanced/module-federation

Defines setup and teardown functions to start an HTTP server on port 3001 before tests and close it after. Used with globalSetup in Rstest config to ensure the remote is reachable before test workers import the host.

```typescript
import { createServer, type Server } from 'node:http';

let server: Server;

export async function setup() {
  server = createServer(/* serve the remote's build output */);
  await new Promise<void>((resolve) => server.listen(3001, resolve));
}

export async function teardown() {
  await new Promise<void>((resolve) => server.close(() => resolve()));
}
```

--------------------------------

### Install identity-obj-proxy with deno

Source: https://rstest.rs/guide/basic/css

Install identity-obj-proxy as a dev dependency using deno.

```bash
deno add npm:identity-obj-proxy -D
```

--------------------------------

### Install @rstest/adapter-rspack with deno

Source: https://rstest.rs/integration/rspack/

Install the adapter as a dev dependency using deno.

```bash
deno add npm:@rstest/adapter-rspack -D
```

--------------------------------

### Install identity-obj-proxy with bun

Source: https://rstest.rs/guide/basic/css

Install identity-obj-proxy as a dev dependency using bun.

```bash
bun add identity-obj-proxy -D
```

--------------------------------

### Install @rstest/adapter-rslib with bun

Source: https://rstest.rs/integration/rslib/

Install the adapter as a dev dependency using bun.

```bash
bun add @rstest/adapter-rslib -D
```

--------------------------------

### Install @rstest/adapter-rspack with bun

Source: https://rstest.rs/integration/rspack/

Install the adapter as a dev dependency using bun.

```bash
bun add @rstest/adapter-rspack -D
```

--------------------------------

### Install dependencies with pnpm

Source: https://rstest.rs/guide/framework/react

Installs the same dependencies using pnpm.

```bash
pnpm add @rstest/core @rsbuild/plugin-react @testing-library/react @testing-library/jest-dom happy-dom -D
```

--------------------------------

### Install @rstest/adapter-rsbuild with deno

Source: https://rstest.rs/integration/rsbuild/

Install the Rsbuild adapter as a dev dependency using deno.

```bash
deno add npm:@rstest/adapter-rsbuild -D
```

--------------------------------

### Install @rslint/core with deno

Source: https://rstest.rs/integration/rslint

Install the @rslint/core package as a dev dependency using deno.

```bash
deno add npm:@rslint/core -D
```

--------------------------------

### Install dependencies with deno

Source: https://rstest.rs/guide/framework/react

Installs the same dependencies using deno with npm: prefixes.

```bash
deno add npm:@rstest/core npm:@rsbuild/plugin-react npm:@testing-library/react npm:@testing-library/jest-dom npm:happy-dom -D
```

--------------------------------

### Install dependencies with yarn

Source: https://rstest.rs/guide/framework/react

Installs the same dependencies using yarn.

```bash
yarn add @rstest/core @rsbuild/plugin-react @testing-library/react @testing-library/jest-dom happy-dom -D
```

--------------------------------

### Install @rstest/core with deno

Source: https://rstest.rs/guide/migration/jest

Install Rstest as a development dependency using deno.

```bash
deno add npm:@rstest/core -D
```

--------------------------------

### Install @rstest/adapter-rsbuild with bun

Source: https://rstest.rs/integration/rsbuild/

Install the Rsbuild adapter as a dev dependency using bun.

```bash
bun add @rstest/adapter-rsbuild -D
```

--------------------------------

### Install @rstest/adapter-rslib with pnpm

Source: https://rstest.rs/integration/rslib/

Install the adapter as a dev dependency using pnpm.

```bash
pnpm add @rstest/adapter-rslib -D
```

--------------------------------

### Install identity-obj-proxy with pnpm

Source: https://rstest.rs/guide/basic/css

Install identity-obj-proxy as a dev dependency using pnpm.

```bash
pnpm add identity-obj-proxy -D
```

--------------------------------

### Install @rstest/core with bun

Source: https://rstest.rs/guide/migration/jest

Install Rstest as a development dependency using bun.

```bash
bun add @rstest/core -D
```

--------------------------------

### Install @rslint/core with bun

Source: https://rstest.rs/integration/rslint

Install the @rslint/core package as a dev dependency using bun.

```bash
bun add @rslint/core -D
```

--------------------------------

### Install other Playwright browsers

Source: https://rstest.rs/guide/browser-testing/getting-started

Install Firefox, WebKit, or all browsers. Comments show each option.

```bash
# Install Firefox
npx playwright install firefox

# Install WebKit (Safari)
 npx playwright install webkit

# Install all browsers
npx playwright install
```

--------------------------------

### Install identity-obj-proxy with npm

Source: https://rstest.rs/guide/basic/css

Install identity-obj-proxy as a dev dependency using npm.

```bash
npm add identity-obj-proxy -D
```

--------------------------------

### Install @rstest/adapter-rslib with npm

Source: https://rstest.rs/integration/rslib/

Install the adapter as a dev dependency using npm.

```bash
npm add @rstest/adapter-rslib -D
```

--------------------------------

### Install identity-obj-proxy with yarn

Source: https://rstest.rs/guide/basic/css

Install identity-obj-proxy as a dev dependency using yarn.

```bash
yarn add identity-obj-proxy -D
```

--------------------------------

### Install happy-dom with bun

Source: https://rstest.rs/config/test/test-environment

Install the happy-dom package as a dev dependency using bun.

```bash
bun add happy-dom -D
```

--------------------------------

### beforeEach basic setup

Source: https://rstest.rs/api/runtime-api/test-api/hooks

Runs setup logic before each test in the current suite. The callback can be async.

```typescript
import { beforeEach } from '@rstest/core';

beforeEach(async () => {
  // Setup logic before each test
});
```

--------------------------------

### runCLI() usage example

Source: https://rstest.rs/api/javascript-api/instance

Runs the Rstest CLI in the current process. It parses 'argv', sets 'process.exitCode', and installs signal handling. The 'argv' matches Node.js 'process.argv' shape; the first two entries are ignored, and command, filters, and flags start at index 2.

```javascript
import { runCLI } from '@rstest/core/api';

runCLI({
  argv: [...process.argv.slice(0, 2), 'run', 'src/foo.test.ts', '--update'],
});
```

--------------------------------

### Example output for a React project

Source: https://rstest.rs/guide/browser-testing/getting-started

Shows the expected output when running the initialization command on a React project. It lists detected settings, created files, and next steps.

```text
Set up Rstest browser mode

  Detecting project...
  ✓ Found React 19.0.0
  ✓ Using playwright as browser provider
  ✓ Test directory: tests/

  Created files:
    - rstest.browser.config.ts
    - tests/Counter.jsx
    - tests/Counter.test.jsx
    - Updated package.json

  Next steps:
    pnpm i
    pnpm dlx playwright install --with-deps
    pnpm run test:browser

└ Done!
```

--------------------------------

### Prompt to trigger migrate-to-rstest skill

Source: https://rstest.rs/guide/start/ai

Example natural language prompt to trigger the installed migrate-to-rstest skill after installation.

```text
Help me migrate this Playwright Test project to @rstest/playwright
```

--------------------------------

### Global setup file with named functions

Source: https://rstest.rs/config/test/global-setup

Recommended format for a global setup file, exporting async setup and teardown functions. Either export can be omitted, but a file exporting neither and no default function fails the run.

```TypeScript
// global-setup.ts

export async function setup() {
  console.log('Setting up test environment...');

  // Initialize database, start services, etc.
  // await startDatabase();
}

export async function teardown() {
  console.log('Tearing down test environment...');

  // Cleanup resources
  // await stopDatabase();
}
```

--------------------------------

### rs.mocked usage example

Source: https://rstest.rs/api/runtime-api/rstest/mock-functions

Example of using rs.mocked to get type hints for a mocked module. After mocking with rs.mock, rs.mocked returns the same object but with TypeScript types that include mock methods.

```typescript
import { myModule } from './myModule';

rs.mock('./myModule', { spy: true });

// TypeScript now knows myModule.method is a MockInstance
const mockedModule = rs.mocked(myModule);

mockedModule.method.mockReturnValue('mocked');
```

--------------------------------

### Example projects configuration with defineConfig and defineInlineProject

Source: https://rstest.rs/config/test/projects

Shows how to define multiple test projects using directories, glob patterns, config files, and inline project configs. Inline projects require a name, and use defineInlineProject.

```typescript
import { defineConfig, defineInlineProject } from '@rstest/core';

export default defineConfig({
  projects: [
    // A monorepo: each package directory is a project
    'packages/*',

    // All projects under the apps directory that provide an rstest config file
    'apps/**/rstest.config.ts',

    // A specific project directory
    '<rootDir>/services/auth',

    // A specific project's config file
    './projects/web/rstest.config.ts',

    // inline project configs
    defineInlineProject({
      name: 'node',
      include: ['tests/node/**/*.{test,spec}.{js,cjs,mjs,ts,tsx}'],
    }),
    defineInlineProject({
      name: 'react',
      include: ['tests/react/**/*.{test,spec}.{js,cjs,mjs,ts,tsx}'],
      testEnvironment: 'jsdom',
    }),
  ],
});
```

--------------------------------

### Install coverage provider and run tests with coverage

Source: https://rstest.rs/guide/advanced/ci

Install the default Istanbul coverage provider and run tests with coverage enabled using the --coverage flag.

```bash
pnpm add @rstest/coverage-istanbul -D
pnpm rstest --coverage
```

--------------------------------

### Run rstest init

Source: https://rstest.rs/guide/basic/cli

Creates starter configuration for supported project types. Run without arguments to use the default initializer.

```bash
npx rstest init
```

--------------------------------

### Assertion error with default truncateThreshold (40)

Source: https://rstest.rs/config/test/chai-config

Example output showing how long arrays or objects get truncated with the default threshold of 40 characters.

```text
AssertionError: expected [ 1, 2, [ 3, [ 4 ], ... ] ] to strictly equal
[ 1, 2, [ 3 ] ]
```

--------------------------------

### rstest.run() example

Source: https://rstest.rs/api/javascript-api/instance

Shows how to create an Rstest instance and run a test cycle with filters, then log the status and summary.

```javascript
import { createRstest } from '@rstest/core/api';

const rstest = await createRstest({
  config: {
    include: ['src/**/*.test.ts'],
  },
});

const result = await rstest.run({
  filters: ['"src/foo.test.ts"'],
});

console.log(result.status);
console.log(result.summary.tests);
```

--------------------------------

### Simple custom reporter

Source: https://rstest.rs/api/javascript-api/reporter

An example of a simple custom reporter that logs test file starts, test case results, and a summary at the end of the test run.

```APIDOC
## Simple custom reporter

### Description
An example of a simple custom reporter that logs test file starts, test case results, and a summary at the end of the test run.

### Code Example
```typescript
import type { Reporter } from '@rstest/core';

const simpleReporter: Reporter = {
  onTestFileStart(test) {
    console.log(`📁 ${test.testPath}`);
  },

  onTestCaseResult(result) {
    const status = result.status === 'pass' ? '✅' : '❌';
    console.log(`${status} ${result.name}`);
  },

  onTestRunEnd({ results }) {
    const passed = results.filter((r) => r.status === 'pass').length;
    const failed = results.filter((r) => r.status === 'fail').length;
    console.log(`\n📊 ${passed} passed, ${failed} failed`);
  },
};
```
```

--------------------------------

### Run rstest init with browser initializer

Source: https://rstest.rs/guide/basic/cli

Creates starter configuration using the `browser` initializer, which is currently the only available initializer.

```bash
npx rstest init browser
```

--------------------------------

### Define Rstest config with defineConfig in rstest.config.ts

Source: https://rstest.rs/guide/basic/configure-rstest

Use defineConfig from @rstest/core in a TypeScript configuration file to get type hints and autocompletion. This example sets testEnvironment to 'node'.

```typescript
import { defineConfig } from '@rstest/core';

export default defineConfig({
  testEnvironment: 'node',
});
```

--------------------------------

### rs.doMockRequire: mock applied only after execution

Source: https://rstest.rs/api/runtime-api/rstest/mock-modules

Use rs.doMockRequire to mock a CommonJS module only for subsequent require() calls. The mock is not hoisted, so earlier require() calls load the original module. The example shows that the first require() gets the original sum, and after calling rs.doMockRequire, the next require() gets the mocked sum.

```javascript
test('doMockRequire only affects later require calls', () => {
  const { sum } = require('./math.cjs');
  expect(sum(1, 2)).toBe(3);

  rs.doMockRequire('./math.cjs', () => ({
    sum: (a, b) => a + b + 100,
  }));

  const { sum: mockedSum } = require('./math.cjs');
  expect(mockedSum(1, 2)).toBe(103);
});
```

--------------------------------

### Run rstest init browser with --yes flag

Source: https://rstest.rs/guide/basic/cli

Skips the interactive prompt and applies the default setup when initializing with the browser initializer.

```bash
npx rstest init browser --yes
```

--------------------------------

### onTestFinished hook usage

Source: https://rstest.rs/api/runtime-api/test-api/hooks

Registers a cleanup function that runs after the test finishes, regardless of the test result. This hook is called after afterEach. In the example, it closes a server started in the test.

```typescript
import { onTestFinished, test } from '@rstest/core';

test('test server', () => {
  const server = startServer();
  // Register a cleanup function to close the server after the test
  onTestFinished(() => server.close());

  server.listen(3000, () => {
    console.log('Server is running on port 3000');
  });
});
```

--------------------------------

### Example: initial run with failures

Source: https://rstest.rs/config/test/only-failures

Shows the output of a full test run where 2 of 14 test files failed.

```bash
npx rstest

 Test Files 2 failed | 12 passed
```

--------------------------------

### rstest-plugin.ts: modifyRstestConfig usage

Source: https://rstest.rs/config/build/plugins

Example of a Rsbuild plugin that uses modifyRstestConfig to set the include pattern for test discovery. The plugin must be registered during the setup phase; registering later is too late.

```typescript
import type { RsbuildPlugin } from '@rsbuild/core';
import type { RstestExposeAPI } from '@rstest/core';

export const myPlugin = (): RsbuildPlugin => ({
  name: 'modify-rstest-config',
  setup(api) {
    const rstestApi = api.useExposed<RstestExposeAPI>('rstest');

    rstestApi?.modifyRstestConfig((config) => {
      config.include = ['**/*.plugin.test.ts'];
    });
  },
});
```

--------------------------------

### Example output with heap usage

Source: https://rstest.rs/config/test/log-heap-usage

Example output after setting `logHeapUsage` to `true`, showing heap usage for each test file.

```text
 ✓ test/index.test.ts (2) 11 MB heap used
 ✓ test/index1.test.ts (2) 11 MB heap used

 Test Files 2 passed
      Tests 2 passed | 2 skipped (4)
   Duration 233ms (build 175ms, tests 58ms)
```

--------------------------------

### mock.invocationCallOrder - Global call order

Source: https://rstest.rs/api/runtime-api/rstest/mock-instance

An array of numbers representing the order in which the mock was called, shared across all mocks. The index starts from 1. The example shows the order for two mocks.

```javascript
const fn1 = rs.fn();
const fn2 = rs.fn();
fn1();
fn2();
fn1();
console.log(fn1.mock.invocationCallOrder); // [1, 3]
console.log(fn2.mock.invocationCallOrder); // [2]
```

--------------------------------

### expect.getState / expect.setState - Access and modify matcher state

Source: https://rstest.rs/api/runtime-api/test-api/expect

Gets the current matcher state and sets partial state. The example shows reading currentTestName and updating it, with the console output confirming the change.

```javascript
const state = expect.getState();
console.log(state.currentTestName);
expect.setState({ currentTestName: 'custom name' });
console.log(expect.getState().currentTestName); // will output 'custom name'
```

--------------------------------

### Install Node.js LTS via nvm

Source: https://rstest.rs/guide/start/quick-start

Commands to install and switch to Node.js LTS using nvm.

```bash
# Install Node.js LTS
nvm install --lts
# Switch to Node.js LTS
nvm use --lts
```

--------------------------------

### Debug with pool.execArgv and maxWorkers: 1

Source: https://rstest.rs/config/test/pool

Combine `pool.execArgv` with `maxWorkers: 1` to run files one at a time for easier debugging. This example passes `--inspect-brk` to workers, enabling the inspector to break on start.

```TypeScript
import { defineConfig } from '@rstest/core';

export default defineConfig({
  pool: {
    maxWorkers: 1,
    execArgv: ['--inspect-brk'],
  },
});
```

--------------------------------

### Using request fixture for API client

Source: https://rstest.rs/guide/basic/e2e-testing

Use the request fixture when you only need Playwright's API client and do not need to launch a browser. The example performs a GET request and asserts the response is ok.

```typescript
import { expect, test } from '@rstest/playwright';

test('health check', async ({ request }) => {
  const response = await request.get('http://localhost:3000/health');

  expect(response.ok()).toBe(true);
});
```

--------------------------------

### Enable headless mode in CI

Source: https://rstest.rs/config/test/browser

Sets `browser.headless` to `true` in `rstest.config.ts` for CI environments. The default is `true` in CI and `false` locally. Includes a GitHub Actions workflow example that installs dependencies and runs tests.

```typescript
import { defineConfig } from '@rstest/core';

export default defineConfig({
  browser: {
    enabled: true,
    provider: 'playwright',
    headless: true,
  },
});
```

```yaml
# .github/workflows/test.yml
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm install
      - run: npx playwright install chromium
      - run: npm test
```

--------------------------------

### setTestIdAttribute in setup file

Source: https://rstest.rs/api/runtime-api/browser-mode/locator

Configures setTestIdAttribute in a setup file to apply consistently to all tests. The setup file is referenced in the config via setupFiles.

```typescript
import { setTestIdAttribute } from '@rstest/browser';

await setTestIdAttribute('data-qa');
```

```typescript
export default defineConfig({
  setupFiles: ['./rstest.setup.ts'],
});
```

--------------------------------

### Write first test with @testing-library/react

Source: https://rstest.rs/guide/framework/react

Creates src/App.test.tsx to render App and assert 'Hello World' is in the document.

```tsx
import { expect, test } from '@rstest/core';
import { render, screen } from '@testing-library/react';
import App from './App';

test('renders greeting', () => {
  render(<App />);
  expect(screen.getByText('Hello World')).toBeInTheDocument();
});
```

--------------------------------

### Install @rstest/coverage-istanbul with deno

Source: https://rstest.rs/config/test/coverage

Install the Istanbul coverage provider package using deno.

```bash
deno add npm:@rstest/coverage-istanbul -D
```

--------------------------------

### Example: query, interaction, and assertion

Source: https://rstest.rs/api/runtime-api/browser-mode/

A complete example showing how to use page to create a Locator, perform actions like fill and click, and assert visibility with expect.element.

```APIDOC
## Example: query, interaction, and assertion

### Description
Demonstrates the usage of `page` to create a Locator, perform actions, and assert element state.

### Code Example
```typescript
import { page } from '@rstest/browser';
import { expect, test } from '@rstest/core';

test('submits form', async () => {
  await page.getByLabel('Email').fill('[email protected]');
  await page.getByRole('button', { name: 'Submit' }).click();
  await expect.element(page.getByText('Done')).toBeVisible();
});
```

### Explanation
- `page` creates a Locator for the element with label 'Email' and fills it.
- `page` creates a Locator for the button with role 'button' and name 'Submit' and clicks it.
- `expect.element(locator)` performs a visibility assertion on the Locator for text 'Done'.
```

--------------------------------

### Create a new Rslib + Rstest project with --tools rstest

Source: https://rstest.rs/integration/rslib/

Use this command to scaffold a new project with Rstest and demo tests. Run `npm run test` to execute the tests.

```bash
npx create-rslib --template react-ts --tools rstest --dir my-project
```

--------------------------------

### Install runtime loader for TypeScript require hook

Source: https://rstest.rs/guide/debug/troubleshooting

Install a runtime loader like @swc-node/register or ts-node to handle CommonJS-style TypeScript files. Rstest does not install these loaders for you.

```bash
npm add -D @swc-node/register
# or: npm add -D ts-node
```

--------------------------------

### Create Rstest instance and inspect context

Source: https://rstest.rs/api/javascript-api/instance

Shows how to create an Rstest instance with a project configuration and then log the context's version, rootPath, and project details. The context is read-only and resolved once at instance creation.

```javascript
import { createRstest } from '@rstest/core/api';

const rstest = await createRstest({
  config: {
    projects: [
      {
        name: 'unit',
        include: ['tests/**/*.test.ts'],
      },
    ],
  },
});

console.log(rstest.context.version);
console.log(rstest.context.rootPath);

for (const project of rstest.context.projects) {
  console.log(project.name, project.rootPath);
}
```

--------------------------------

### Install @rstest/core and @rstest/browser with deno

Source: https://rstest.rs/guide/browser-testing/getting-started

Install the Rstest core package and Browser Mode support package using deno. Add as dev dependencies.

```bash
deno add npm:@rstest/core npm:@rstest/browser -D
```

--------------------------------

### Install @rstest/adapter-rspack with pnpm

Source: https://rstest.rs/integration/rspack/

Install the adapter as a dev dependency using pnpm.

```bash
pnpm add @rstest/adapter-rspack -D
```

--------------------------------

### Install @rstest/adapter-rspack with yarn

Source: https://rstest.rs/integration/rspack/

Install the adapter as a dev dependency using yarn.

```bash
yarn add @rstest/adapter-rspack -D
```

--------------------------------

### Install @rstest/adapter-rspack with npm

Source: https://rstest.rs/integration/rspack/

Install the adapter as a dev dependency using npm.

```bash
npm add @rstest/adapter-rspack -D
```

--------------------------------

### Boolean option negation examples

Source: https://rstest.rs/guide/basic/cli

Shows how to use the `--no-<option>` prefix to set boolean options to false. The first two commands are equivalent, and the remaining lines demonstrate disabling coverage, global APIs, and auto-clearing mocks.

```bash
# These are equivalent:
npx rstest --isolate false
npx rstest --no-isolate

# More examples:
npx rstest --no-coverage      # Disable coverage
npx rstest --no-globals        # Disable global APIs
npx rstest --no-clearMocks     # Disable auto-clearing mocks
```

--------------------------------

### Install @rstest/adapter-rslib with yarn

Source: https://rstest.rs/integration/rslib/

Install the adapter as a dev dependency using yarn.

```bash
yarn add @rstest/adapter-rslib -D
```