diff --git a/src/wp-includes/class-wp-user.php b/src/wp-includes/class-wp-user.php
index 9fb9f262a1..7badeb7575 100644
--- a/src/wp-includes/class-wp-user.php
+++ b/src/wp-includes/class-wp-user.php
@@ -345,7 +345,6 @@ class WP_User {
 	public function __unset( $key ) {
 		if ( 'id' == $key ) {
 			_deprecated_argument( 'WP_User->id', '2.1', __( 'Use <code>WP_User->ID</code> instead.' ) );
-			$key = 'ID';
 		}
 
 		if ( isset( $this->data->$key ) ) {
diff --git a/tests/phpunit/tests/user.php b/tests/phpunit/tests/user.php
index ff61749259..56db120884 100644
--- a/tests/phpunit/tests/user.php
+++ b/tests/phpunit/tests/user.php
@@ -199,7 +199,7 @@ class Tests_User extends WP_UnitTestCase {
 		// Test 'ID'
 		$this->assertNotEmpty( $user->ID );
 		unset( $user->ID );
-		$this->assertEmpty( $user->ID );
+		$this->assertNotEmpty( $user->ID );
 	}
 
 	// Test meta property magic functions for property get/set/isset.