Test-It

Test-It is a test framework that combines the best of node and the browser.

Features

• Your tests have full access to a Real DOM and Node.js APIs
• Out-of-the-box support for TypeScript, React, Flow, ES Modules, and more
• Same describe, it, expect API as Jest
• Use debug instead of it to open your test in a browser and debug with Chrome DevTools
• Support for snapshot testing via expect(value).toMatchSnapshot()
• Use await TestIt.captureScreenshot() to capture a screenshot of the page (returns a Buffer of PNG data)
• Built-in Visual Regression Testing via expect(pngBuffer).toMatchImageSnapshot()

The Problem

When running in a test framework built on top of node, like Jest, you don't have access to real DOM APIs, like window and document.

Some test frameworks (Jest included) try to get around this by using jsdom, but it has limitations; since there's no layout or rendering engine, you can't test things that rely on:

• What the page looks like (for eg. Visual Regression Testing)
• .getBoundingClientRect()
• document.body.innerText

This is usually solved by running the tests in a real browser, using something like Karma. But, that introduces other limitations:

• You can't use require in your tests, so your tests need to get compiled somehow
• You can't use fs in your tests, so you can't write snapshots or screenshots to disk.

If you want to do something that requires a real DOM as well as require or fs, then you have to write a complex server that ties everything together.

For example, if you want to render individual parts of your application to the DOM, and then perform Visual Regression Testing by taking screenshots of those components, you need to:

• Start a test "server", running in node
• Compile your tests so they can run in a browser (without require)
• Launch a browser, and make it open your compiled tests (via some http server)
• Have the tests communicate with the test server in order to use fs to write screenshots to disk

It's very complicated, and it's a lot to set up.

If there was a test framework that could run code with access to a Real DOM and node APIs, then we wouldn't need any of those things:

• No need for a test server that wraps fs, because you can access fs directly
• No need for test compilation/bundling, because you can use require right in your tests

Test-It is that test framework.

The Solution

When you run your tests in Test-It, you have access to real DOM APIs and all of node's APIs, including require.

Unlike test frameworks built on top of jsdom, the DOM APIs here are real; your tests are running in a real Chromium browser.

But also, unlike test frameworks built on top Karma, the Node APIs here are also real; your tests are running with full access to all node APIs (such as require, fs, etc).

Test-It gives you the best of both worlds.

Installation

First, install @test-it/core and @test-it/cli:

npm install --save-dev @test-it/core @test-it/cli

Then, add the following to your package.json:

"scripts": {
	"test-it": "test-it"
}

Then, run Test-It using npm:

npm run test-it

TypeScript

If you use TypeScript, you can add "./node_modules/@test-it/core/globals.d.ts" to your tsconfig.json's files array to get types for the following globals (which are provided by Test-It):

• expect
• describe
• fdescribe
• xdescribe
• test
• it
• debug
• fit
• xit
• beforeEach
• beforeAll
• before
• afterEach
• afterAll
• after
• TestIt

Usage

By default, Test-It will run against any test files named like *.test.js.

To change this, you can pass glob strings to the test-it CLI:

npm run test-it -- './**/*.spec.js' '!**/node_modules/**'

You can also pass specific filenames:

npm run test-it -- './tests/first.spec.js' './tests/second.spec.js'

For more usage information run npm run test-it -- --help.