Add comprehensive testing framework for both single site and multisite WordPress environments

mu-plugins/multisite-setup.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * Plugin Name: Multisite Setup Helper
+ * Description: Helper plugin to set up multisite testing environment
+ * Version: 1.0.0
+ * Author: WPALLSTARS
+ * License: GPL-2.0-or-later
+ */
+
+// Exit if accessed directly.
+if ( ! defined( 'ABSPATH' ) ) {
+    exit;
+}
+
+/**
+ * Add a filter to allow subdirectory multisite on localhost
+ */
+add_filter( 'allow_subdirectory_install', '__return_true' );
+
+/**
+ * Add a filter to skip domain verification for multisite
+ */
+add_filter( 'multisite_domain_check', '__return_true' );
+
+/**
+ * Add a filter to allow wildcard subdomains
+ */
+add_filter( 'wp_is_large_network', '__return_false' );
+
+/**
+ * Add a filter to allow domain mapping
+ */
+add_filter( 'domain_mapping_warning', '__return_false' );