test: add markTestSkipped()

Author: kenjis

tests/system/Database/Live/SQLite3/AlterTableTest.php

@@ -43,12 +43,15 @@ protected function setUp(): void
     {
         parent::setUp();
 
+        if ($this->db->DBDriver !== 'SQLite3') {
+            $this->markTestSkipped('This test is only for SQLite3.');
+        }
+
         $config = [
             'DBDriver' => 'SQLite3',
             'database' => ':memory:',
             'DBDebug'  => true,
         ];
-
         $this->db    = db_connect($config);
         $this->forge = Database::forge($config);
         $this->table = new Table($this->db, $this->forge);