ENH Let unit tests manipulate the DB before loading fixtures (#11182)

src/Dev/SapphireTest.php

@@ -251,6 +251,14 @@ abstract class SapphireTest extends TestCase implements TestOnly
         return $this->requireDefaultRecordsFrom;
     }
 
+    /**
+     * Called after the database is created, but before fixtures are loaded.
+     */
+    public function onBeforeLoadFixtures(): void
+    {
+        // no-op - this method is intended to be overridden by subclasses.
+    }
+
     /**
      * Setup  the test.
      * Always sets up in order:

src/Dev/State/FixtureTestState.php

@@ -63,6 +63,7 @@ class FixtureTestState implements TestState
                     $instance->augmentDefaultRecords();
                 }
             }
+            $test->onBeforeLoadFixtures();
             $this->loadFixtures($test);
         }