Document patch base tests.
>>> [!note] Migrated issue
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Reported by: [marcus_johansson](https://www.drupal.org/user/385947)
Related to !1121
>>>
<p>[Tracker]<br>
<strong>Update Summary: </strong>[One-line status update for stakeholders]<br>
<strong>Short Description: </strong>[One-line issue summary for stakeholders]<br>
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<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>Currently testing patch tests is a chore and only a few people can do it. This means a lot of time is spent on this for very minor update paths.</p>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<p>Write a documentation that makes it easier to share the load.</p>
issue