public function testCreateUniqueIndexUsing()
 {
     // CREATE INDEX CONCURRENTLY idx_salary ON employees(last_name, salary);
     $q = new CreateIndexQuery();
     $q->unique('idx_salary')->on('employees', ['last_name', 'salary'])->using('BTREE');
     $this->assertSql('CREATE UNIQUE INDEX `idx_salary` ON `employees` (last_name,salary) USING BTREE', $q);
 }