TypeScript icon, indicating that this package has built-in type declarations

2.3.0 • Public • Published

FicusJS testing


The FicusJS testing package provides lightweight helper functions for web component testing.

This package provides browser globals such as window and document using jsdom which is an implementation of many browser APIs ideal for testing but is not an actual browser.

We recommend using a tool such as Cypress for browser end-to-end tests.

Running tests

This package contains functions intended for a NodeJS environment and not a real browser. It is therefore, best used for fast iteration.

The functions can be used with any NodeJS testing framework.

The following functions are available in the FicusJS testing package.

  • init - a function for initializing the test environment
  • render - a function to render a web component for testing

init function

The init function initializes the NodeJS environment ready for testing.

Simply call init in your set-up hook.

import test from 'ava'
import { init, render } from '@ficusjs/testing'


// if passing options to JSDOM
test.before(() => init({ runScripts: 'dangerously' }))

The init function accepts the following optional arguments:

Name Type Description
options object An object of options to pass to JSDOM

render function

The render function will create a new web component instance for testing.

It returns a DOM instance of the component.

import test from 'ava'
import { init, render } from '@ficusjs/testing'


test('render basic component', async t => {
    const comp = await render('basic-comp', () => import('../src/component.mjs'), { foo: 'bar' })
    t.is(comp.querySelector('p').textContent, 'Basic component with bar')

The render function accepts the following arguments:

Name Type Description
tagName string The web component tag name
importer function A function that registers a web component. This can return a Promise
attrs object An optional object of attributes to set on the component instance

Testing components

Testing web components can be done in a number of ways.

  • verifying that a component renders without throwing using a "smoke test"
  • shallow rendering and testing component output
  • full rendering and testing component lifecycle and state changes

It is a good idea to start with creating basic smoke tests for your components.

Testing that a component mounts and ensures that it doesn't throw during rendering provides a lot of value with very little effort.


This project is licensed under the MIT License - see the LICENSE file for details.

Contributing to FicusJS

Any kind of positive contribution is welcome! Please help us to grow by contributing to the project.

If you wish to contribute, you can work on any features you think would enhance the library. After adding your code, please send us a Pull Request.

Please read CONTRIBUTING for details on our CODE OF CONDUCT, and the process for submitting pull requests to us.


We all need support and motivation. FicusJS is not an exception. Please give this project a ⭐️ to encourage and show that you liked it. Don't forget to leave a star ⭐️ before you move away.

If you found the library helpful, please consider sponsoring us.

Package Sidebar


npm i @ficusjs/testing

Weekly Downloads






Unpacked Size

19.7 kB

Total Files


Last publish


  • fenderstrat85
  • christianletter
  • matt.levy
  • james-cavanagh