Ensure wpmu_delete_blog() is loaded (#818)

Author: srtfisher

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v1.13.1
+
+### Fixed
+
+- Fixed issue with `wpmu_delete_blog()` not being loaded before use.
+
 ## v1.13.0
 
 ### Added

src/mantle/testing/class-utils.php

@@ -189,6 +189,10 @@ public static function delete_all_blogs(): void {
 		// phpcs:disable WordPress.DB,WordPressVIPMinimum.Variables
 		global $wpdb;
 
+		if ( ! function_exists( 'wpmu_delete_blog' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/ms.php';
+		}
+
 		foreach ( $wpdb->get_col( "SELECT blog_id FROM {$wpdb->blogs} WHERE blog_id != 1" ) as $blog_id ) {
 			wpmu_delete_blog( $blog_id, true );
 		}