AddCellphoneMigration::downgrade PHP Method

    public function downgrade()
    {
        $this->dropColumn('foo', 'cellphone');
    }

 public function testUpgradeWithAddColumnByCallable()
 {
     ob_start();
     $this->conn->query('DROP TABLE IF EXISTS foo');
     $this->conn->query('CREATE TABLE foo (id INTEGER PRIMARY KEY, name varchar(32));');
     $migration = new AddCellphoneMigration($this->conn, $this->queryDriver, $this->logger);
     $migration->upgrade();
     $migration->downgrade();
     $this->conn->query('DROP TABLE IF EXISTS foo');
     ob_end_clean();
 }