Panther

Panther is a Drupal module that provides an integration with the Panther library for functional testing of web applications.
It allows you to write tests in PHP using the Panther API, which is built on top of the Symfony BrowserKit and DomCrawler components.

A test looks like:

public function testLoginPage(): void {
   $this->maximizeWindow();
   $this->goToPage('/user/login');
   self::assertPageContains('Log in');
   $this->takeScreenshot('testLoginPage', 'login');
 }