Drupal - SymfonyTestsListener does not exist on PHP Unit Test

Had a similar issue: Solved it by adding the "symfony/phpunit-bridge": "^3.4.3" library.

Removing the line below in phpunit.xml fixes my issue:

<!-- The Symfony deprecation listener has to come after the Drupal listener -->
<listener class="Symfony\Bridge\PhpUnit\SymfonyTestsListener">
</listener>

Not sure if this will cause any issues.

Although the approved answer here shows the exact package that is needed what users may be looking for is to require the "drupal/core-dev" package which contains the needed "symfony/phpunit-bridge" as a dependency.