>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3496673. --> Reported by: [catch](https://www.drupal.org/user/35733) Related to !484 >>> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>Follow-up from <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/drupal_cms/-/work_items/3496652" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/drupal_cms/-/work_items/3496652</a></span>, <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/drupal_cms/-/work_items/3491405" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/drupal_cms/-/work_items/3491405</a></span>, <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/drupal_cms/-/work_items/3494505" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/drupal_cms/-/work_items/3494505</a></span> etc.</p> <p>The performance job currently allows failure, so a build won't fail if performance tests do.</p> <p>I think this runs the risk of problems being introduced and being harder to track down where they came from, so it would be good to have it fail properly.</p> <p>Generally, when performance tests fail due to a change (whether a contrib update or a recipe change), the only thing that needs to happen is to adjust the assertions to the new value. Usually one extra cache get, or query, or 1kb of CSS is fine. Having the test fail and be updated just means we know what's happening when it happens. If it's unexpected, can always open a follow-up to investigate - this is how we handle the majority of changes with core.</p> <p>If something suddenly adds 20 database queries or 30 cache gets or 50kb of CSS, there's probably a problem though - and the only way to find this out is to have precise assertions in the first place.</p> <p>When upcoming releases of contrib modules affect performance tests (which doesn't happen with core). This should be somewhat mitigated by <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/drupal_cms/-/work_items/3496652" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/drupal_cms/-/work_items/3496652</a></span>. If a contrib module adds one extra query in a dev release, a performance test can be adjusted to use assertGreaterThan and assertLessThan instead of assertSame so it passes with both versions, then a follow-up to use assertSame for the new number.</p> <h4 id="summary-steps-reproduce">Steps to reproduce</h4> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <h3 id="summary-remaining-tasks">Remaining tasks</h3> <h3 id="summary-ui-changes">User interface changes</h3> <h3 id="summary-api-changes">API changes</h3> <h3 id="summary-data-model-changes">Data model changes</h3>