API Replace Extension subclasses

src/Context/FixtureContext.php

@@ -23,7 +23,6 @@
 use SilverStripe\Dev\FixtureFactory;
 use SilverStripe\Dev\YamlFixture;
 use SilverStripe\ORM\Connect\TempDatabase;
-use SilverStripe\ORM\DataExtension;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\DB;
 use SilverStripe\Security\Group;
@@ -704,6 +703,7 @@ public function iAddAnExtensionToTheClass($extension, $class)
             class_exists($extension ?? '') && is_subclass_of($extension, Extension::class),
             'Given extension does not extend Extension'
         );
+        /** @var Extension $extension */
 
         // Add the extension to the CLI context
         /** @var Extensible $targetClass */
@@ -741,8 +741,8 @@ class_exists($extension ?? '') && is_subclass_of($extension, Extension::class),
         // Remember to cleanup...
         $this->activatedConfigFiles[] = $destPath;
 
-        // Flush website. We'll need to dev/build too if it's a DataExtension
-        if (is_subclass_of($extension, DataExtension::class)) {
+        // Flush website. We'll need to dev/build too if it's a DataObject
+        if (is_subclass_of($extension->getOwner(), DataObject::class)) {
             $this->getMainContext()->visit('/dev/build?flush');
         } else {
             $this->getMainContext()->visit('/?flush');