@testing-library/svelte NPM

The Problem

You want to write tests for your Svelte components so that they avoid including implementation details, and are maintainable in the long run.

This Solution

The svelte-testing-library is a very lightweight solution for testing Svelte components. It provides light utility functions on top of svelte and dom-testing-library, in a way that encourages better testing practices. Its primary guiding principle is:

The more your tests resemble the way your software is used, the more confidence they can give you.

Installation

This module is distributed via npm which is bundled with node and should be installed as one of your project's devDependencies:

npm install --save-dev @testing-library/svelte

This library has peerDependencies listings for svelte >= 3.

You may also be interested in installing @testing-library/jest-dom so you can use the custom jest matchers.

Setup

We recommend using @testing-library/svelte with Vitest as your test runner. To get started, add the svelteTesting plugin to your Vite or Vitest config.

  // vite.config.js
  import { svelte } from '@sveltejs/vite-plugin-svelte'
+ import { svelteTesting } from '@testing-library/svelte/vite'

  export default defineConfig({
    plugins: [
      svelte(),
+     svelteTesting(),
    ]
  });

See the setup docs for more detailed setup instructions, including for other test runners like Jest.

Svelte 5 support

If you are riding the bleeding edge of Svelte 5, you'll need to either import from @testing-library/svelte/svelte5 instead of @testing-library/svelte, or add an alias to your vite.config.js:

export default defineConfig({
  plugins: [svelte(), svelteTesting()],
  test: {
    alias: {
      '@testing-library/svelte': '@testing-library/svelte/svelte5',
    },
  },
})