As part of the push to deprecate SimpleTest and use PHPUnit as the test runner in Drupal 8, there is the
\Drupal\Tests\BrowserTestBase class. The
BrowserTestBase provides a Mink runner that tests web pages in Drupal. Unlike kernel tests, which require a database and can be run via PHPUnit as well, browser tests use your default database connection. I prefer to run my tests with SQLite as I do not need to have my Docker containers running.
The simplest solution I have found, thus far, is to check the HTTP_USER_AGRENT