Allow test modules to be installed
>>> [!note] Migrated issue
<!-- Drupal.org comment -->
<!-- Migrated from issue #3548635. -->
Reported by: [justafish](https://www.drupal.org/user/161058)
Related to !3 !2 !1
>>>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>Test modules that are hidden unless extension_discovery_scan_tests is set to true</p>
issue