diff --git a/tests/phpunit/tests/kses.php b/tests/phpunit/tests/kses.php
index f6064dc1f4..8ea6f44ffc 100644
--- a/tests/phpunit/tests/kses.php
+++ b/tests/phpunit/tests/kses.php
@@ -1107,6 +1107,11 @@ EOF;
 				'css'      => 'background: conic-gradient(at 0% 30%, red 10%, yellow 30%, #1e90ff 50%)',
 				'expected' => 'background: conic-gradient(at 0% 30%, red 10%, yellow 30%, #1e90ff 50%)',
 			),
+			// `object-position` introduced in 5.7.1.
+			array(
+				'css'      => 'object-position: right top',
+				'expected' => 'object-position: right top',
+			),
 			// Expressions are not allowed.
 			array(
 				'css'      => 'height: expression( body.scrollTop + 50 + "px" )',