Re-using unit test

[smilesrg]

Hello!

Would be super nice if https://github.com/trikoder/oauth2-bundle/blob/v3.x/Tests/Acceptance/TokenEndpointTest.php could be reused in the application. I mean, after library integration, I need to copy-paste the existing test and change the request URL to /oauth2/token. If, for example, I could extend this test and replace this URL somehow, the test could be easily re-used and integrated into the application.