Backbone Testing Library


DOM testing utilities for Backbone with an API that mirrors React Testing Library.

$3

Interested in working on projects like this? Close is looking for great engineers to join our team!

Why would you want this... It's nearly 2021!?

At Close a large portion of our app is still written in Backbone and we're carefully
transitioning this to React. We created this library as a way to write tests on our
Backbone components in the style of React Testing Library. This means, as we port
components over, we are able to use the same tests with very minimal changes and so
minimize regressions in our app. While we wouldn't recommend building a brand new FE app
with Backbone, we're open sourcing this to help anyone else looking to transition a
legacy codebase.

Installation

This module is distributed via npm which is bundled with node and
should be installed as one of your project's devDependencies.
This library also has peerDependencies listings for @testing-library/dom:

``
npm install --save-dev @closeio/backbone-testing-library @testing-library/dom
`

or

for installation via yarn

`
yarn add --dev @closeio/backbone-testing-library @testing-library/dom
`

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

Example

`javascript
// models/HiddenMessageModel.js

import Backbone from 'backbone';

const HiddenMessageModel = Backbone.Model.extend({
defaults: {
message: '',
showMessage: false,
},
});

export default HiddenMessageModel;
`

`javascript
// views/HiddenMessageView.js

import Backbone from 'backbone';

const HiddenMessageView = Backbone.View.extend({
events: {
'change #toggle': 'setShowMessage',
},

initialize({ model }) {
this.model = model;
this.model.on('change', this.render.bind(this));
},

setShowMessage(e) {
this.model.set('showMessage', e.target.checked);
},

template({ showMessage, message }) {
return

;
},

render() {
this.$el.html(this.template(this.model.attributes));
},
});

export default HiddenMessageView;
`

`javascript
// views/HiddenMessageView.test.js

// these imports are something you'd normally configure Jest to import for you
// automatically. Learn more in the setup docs: https://testing-library.com/docs/react-testing-library/setup#cleanup
import '@testing-library/jest-dom';
// NOTE: jest-dom adds handy assertions to Jest and is recommended, but not required

import { render, fireEvent } from '@closeio/backbone-testing-library';

import HiddenMessageModel from '../models/HiddenMessageModel';
import HiddenMessageView from './HiddenMessageView';

test('shows the children when the checkbox is checked', () => {
const testMessage = 'Test Message';
const testModel = new HiddenMessageModel({
message: testMessage,
});

// The queries you'd expect from React Testing Library are returned from render, as are
// view, container, baseElement, debug and unmount. We also hook into React
// Testing Library's RTL_SKIP_AUTO_CLEANUP const to auto unmount views in afterEach
const { queryByText, getByLabelText, getByText } = render(HiddenMessageView, {
model: testModel,
});

// query* functions will return the element or null if it cannot be found
// get* functions will return the element or throw an error if it cannot be found
expect(queryByText(testMessage)).toBeNull();

// the queries can accept a regex to make your selectors more resilient to content tweaks and changes.
fireEvent.click(getByLabelText(/show/i));

// .toBeInTheDocument() is an assertion that comes from jest-dom
// otherwise you could use .toBeDefined()
expect(getByText(testMessage)).toBeInTheDocument();
});
`

render Parameters

- View - the first argument is the Backbone.View Class to test, it will be
instantiated by the render function
- options - optional - the second argument is an options object with the following
parameters:
- container - optional - behaves like RTL's container
by default creates a div and appends it to document.body
- baseElement - optional - behaves like RTL's baseElement
if container is specified, then it defaults to that, otherwise this defaults to document.body
- autoRender - optional - this defaults to true. Sometimes you may want to
assert on something in between your Backbone.View's initialize and render methods, if
so you can pass false here and call render manually on the returned view instance.
- ...options - any other properties will be passed through as options to the
Backbone.View's constructor. For example, you could add el if you wanted to manually
provide this to the view rather than have Backbone auto create it. You'll also likely
often want to pass a model.

render Result

The render method returns an object that has a few properties:

- ...queries - The most important feature of render is that the queries from DOM Testing Library
are automatically returned with their first argument bound to the baseElement, which
defaults to document.body
- view - The Backbone view instance itself.
- container - behaves like RTL's container
returns either a div autocreated for you, or the container passed to render. To get
the root element of your rendered element, use container.firstChild _or_ view.el.
- baseElement - behaves like RTL's baseElement
returns either document.body or the baseElement passed to render.
- debug - behaves like RTL's debug
this function is a shortcut for console.log(prettyDOM(baseElement)).
- unmount - calls remove on the Backbone.View instance and cleans up the container
element. Useful for testing what happens when your view is removed from the page.
By default, when RTL_SKIP_AUTO_CLEANUP is false, cleanup is called in every afterEach
block which runs render, which means you don't need to manually unmount your views if
you're not testing remove. While it might seem odd to rely on a ENV var from another
library, our intention here is that this library is run in tandem with RTL and behaves
identically for porting components.

License

MIT © Close