diff --git a/plugins/ActivityPub/tests/ActivityPubTestCase.php b/plugins/ActivityPub/tests/ActivityPubTestCase.php
new file mode 100644
index 0000000000..c417fb2ab2
--- /dev/null
+++ b/plugins/ActivityPub/tests/ActivityPubTestCase.php
@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Plugin\ActivityPub\tests;
+
+use App\Core\DB\DB;
+use App\Util\GNUsocialTestCase;
+use Plugin\ActivityPub\Util\Model\Activity;
+use Plugin\ActivityPub\Util\Model\Actor;
+use Plugin\ActivityPub\Util\Model\Note;
+
+class ActivityPubTestCase extends GNUsocialTestCase
+{
+    private static bool $loaded_fixtures = false;
+    private static string $fixtures_path = INSTALLDIR . '/plugins/ActivityPub/tests/fixtures';
+
+    public static function fixturesPath(string $path, string $ontology = 'gnusocial'): string
+    {
+        return self::$fixtures_path . \DIRECTORY_SEPARATOR . $ontology . \DIRECTORY_SEPARATOR . $path;
+    }
+
+    public static function setUpBeforeClass(): void
+    {
+        static::bootKernel();
+        if (!static::$loaded_fixtures) {
+            static::loadFixtures();
+        }
+        static::$loaded_fixtures = true;
+    }
+
+    public static function loadFixtures(string $ontology = 'gnusocial'): void
+    {
+        /*
+         * Beware that it's important to Load Actors, Objects, Activities in this sequence
+         * because we're running offline tests here.
+         */
+
+        // Load Actors
+        $person = Actor::fromJson(file_get_contents(self::fixturesPath('objects/person.jsonld', $ontology)));
+        DB::flush();
+        $group = Actor::fromJson(file_get_contents(self::fixturesPath('objects/group.jsonld', $ontology)));
+        DB::flush();
+
+        // Load Objects
+        $note = Note::fromJson(file_get_contents(self::fixturesPath('objects/note.jsonld', $ontology)));
+        DB::flush();
+        $page = Note::fromJson(file_get_contents(self::fixturesPath('objects/page.jsonld', $ontology)));
+        DB::flush();
+        $reply = Note::fromJson(file_get_contents(self::fixturesPath('objects/reply.jsonld', $ontology)));
+        DB::flush();
+
+        // Load Activities
+        $create_note = Activity::fromJson(file_get_contents(self::fixturesPath('activities/create_note.jsonld', $ontology)));
+        DB::flush();
+        $create_page = Activity::fromJson(file_get_contents(self::fixturesPath('activities/create_page.jsonld', $ontology)));
+        DB::flush();
+        $create_reply = Activity::fromJson(file_get_contents(self::fixturesPath('activities/create_reply.jsonld', $ontology)));
+        DB::flush();
+    }
+}