diff --git a/tests/phpunit/includes/abstract-testcase.php b/tests/phpunit/includes/abstract-testcase.php
index 4abd973c73..b33991af64 100644
--- a/tests/phpunit/includes/abstract-testcase.php
+++ b/tests/phpunit/includes/abstract-testcase.php
@@ -677,7 +677,7 @@ abstract class WP_UnitTestCase_Base extends PHPUnit\Framework\TestCase {
 	 * @param string $message  Optional. Message to display when the assertion fails.
 	 */
 	public function assertDiscardWhitespace( $expected, $actual, $message = '' ) {
-		$this->assertEquals( preg_replace( '/\s*/', '', $expected ), preg_replace( '/\s*/', '', $actual, $message ) );
+		$this->assertEquals( preg_replace( '/\s*/', '', $expected ), preg_replace( '/\s*/', '', $actual ), $message );
 	}
 
 	/**