PHPCS 4.x | Test suite broken #3120
Description
While making some changes for PHPCS 4.x, I wasn't getting an expected error when I ran the unit tests on PHP 7.4/PHPUnit 9.x and when I looked more closely, I realized that the sniff tests weren't being run at all, only the "Core" tests were being run.
The same can be seen in the Travis runs:
PHP 7.2:
$ vendor/bin/phpunit tests/AllTests.php
PHPUnit 8.5.8 by Sebastian Bergmann and contributors.
............................................................... 63 / 567 ( 11%)
<snip>
...........................................S................... 567 / 567 (100%)
PHP 7.3:
$ vendor/bin/phpunit tests/AllTests.php
PHPUnit 9.3.10 by Sebastian Bergmann and contributors.
............................................................... 63 / 368 ( 17%)
<snip>
........................S............................ 368 / 368 (100%)
PHP 7.4:
$ vendor/bin/phpunit tests/AllTests.php
PHPUnit 9.3.10 by Sebastian Bergmann and contributors.
............................................................... 63 / 368 ( 17%)
<snip>
........................S............................ 368 / 368 (100%)
PHP nightly:
$ vendor/bin/phpunit tests/AllTests.php
PHPUnit 9.3.10 by Sebastian Bergmann and contributors.
............................................................... 63 / 368 ( 17%)
<snip>
........................S............................ 368 / 368 (100%)
This will need further investigation.