diff --git a/tests/phpunit/tests/multisite/isEmailAddressUnsafe.php b/tests/phpunit/tests/multisite/isEmailAddressUnsafe.php
index 51a29ef4d9..93bc24bda5 100644
--- a/tests/phpunit/tests/multisite/isEmailAddressUnsafe.php
+++ b/tests/phpunit/tests/multisite/isEmailAddressUnsafe.php
@@ -1,5 +1,7 @@
 <?php
 
+if ( is_multisite() ) :
+
 /**
  * @group multisite
  */
@@ -119,3 +121,5 @@ class Tests_Multisite_IsEmailAddressUnsafe extends WP_UnitTestCase {
 		);
 	}
 }
+
+endif;