Improve wp acorn compability

tests/bootstrap.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * WordPress isn't loaded in unit tests. Define ABSPATH as insurance so any code
+ * that transitively pulls in a file guarded by `defined('ABSPATH') || exit;`
+ * fails loudly instead of vanishing mid-load. BootCoordinator itself needs no WP
+ * constants — Brain\Monkey mocks did_action()/do_action() per test.
+ */
+if (! defined('ABSPATH')) {
+    define('ABSPATH', __DIR__ . '/');
+}
+
+require_once __DIR__ . '/../vendor/autoload.php';