diff --git a/tests/phpunit/tests/customize/nav-menu-setting.php b/tests/phpunit/tests/customize/nav-menu-setting.php
index dd1b5843ba..fd66d4ca93 100644
--- a/tests/phpunit/tests/customize/nav-menu-setting.php
+++ b/tests/phpunit/tests/customize/nav-menu-setting.php
@@ -215,7 +215,7 @@ class Test_WP_Customize_Nav_Menu_Setting extends WP_UnitTestCase {
 		$menus = wp_get_nav_menus();
 		$menus_ids = wp_list_pluck( $menus, 'term_id' );
 		$i = array_search( $menu_id, $menus_ids );
-		$this->assertNotFalse( $i, 'Update-previewed menu does not appear in wp_get_nav_menus()' );
+		$this->assertInternalType( 'int', $i, 'Update-previewed menu does not appear in wp_get_nav_menus()' );
 		$filtered_menu = $menus[ $i ];
 		$this->assertEquals( 'Name 2', $filtered_menu->name );
 	}
@@ -260,7 +260,7 @@ class Test_WP_Customize_Nav_Menu_Setting extends WP_UnitTestCase {
 		$menus = wp_get_nav_menus();
 		$menus_ids = wp_list_pluck( $menus, 'term_id' );
 		$i = array_search( $menu_id, $menus_ids );
-		$this->assertNotFalse( $i, 'Insert-previewed menu was not injected into wp_get_nav_menus()' );
+		$this->assertInternalType( 'int', $i, 'Insert-previewed menu was not injected into wp_get_nav_menus()' );
 		$filtered_menu = $menus[ $i ];
 		$this->assertEquals( 'New Menu Name 1', $filtered_menu->name );
 	}