PHPCS has identified that some of the OAuthAuthentication PHPUnit tests are missing @covers tags. Those tags
are necessary for PHPUnit to accurately calculate test coverage.
See the PHPUnit documentation for how to use it.
Once the tags have been added, the MissingCovers sniff should be re-enabled in .phpcs.xml.
If you are not already familiar with PHPUnit tests and would like to learn more about this: https://www.mediawiki.org/wiki/Manual:PHP_unit_testing/Writing_unit_tests has links to some good material on the basics of testing.
Mentors: @Legoktm