Types of tests

PHPUnit

Most testing in current versions of Drupal is done under the PHPUnit framework. Drupal supports unit, integration, and system/functional testing using the PHPUnit framework.

In Drupal, there are 4 types of PHPUnit tests.

Unit

PHPUnit-based tests with minimal dependencies.

Base class: Drupal\Tests\UnitTestCase class.

Kernel

PHPUnit-based tests with a bootstrapped kernel, and a minimal number of extensions enabled.

Base class: Drupal\KernelTests\KernelTestBase class.

Functional

PHPUnit-based tests with a full booted Drupal instance.

Base class: Drupal\Tests\BrowserTestBase.

FunctionalJavascript

PHPUnit-based tests that use Webdriver to perform tests of Javascript and Ajax functionality in the browser.

There is a base class for general testing, Drupal\FunctionalJavascriptTests\WebDriverTestBase, and one for performance testing, Drupal\FunctionalJavascriptTests\PerformanceTestBase.

Nightwatch

Drupal project uses the Nightwatch framework for JavaScript testing. See JavaScript testing using Nightwatch.