function test_1_transactions()
{
DB::$nested_transactions = true;
$depth = DB::startTransaction();
$this->assert($depth === 1);
DB::query("UPDATE accounts SET age=%i WHERE username=%s", 700, 'Abe');
$depth = DB::startTransaction();
$this->assert($depth === 2);
DB::query("UPDATE accounts SET age=%i WHERE username=%s", 800, 'Abe');
$depth = DB::startTransaction();
$this->assert($depth === 3);
$this->assert(DB::transactionDepth() === 3);
DB::query("UPDATE accounts SET age=%i WHERE username=%s", 500, 'Abe');
$depth = DB::commit();
$this->assert($depth === 2);
$age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
$this->assert($age == 500);
$depth = DB::rollback();
$this->assert($depth === 1);
$age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
$this->assert($age == 700);
$depth = DB::commit();
$this->assert($depth === 0);
$age = DB::queryFirstField("SELECT age FROM accounts WHERE username=%s", 'Abe');
$this->assert($age == 700);
DB::$nested_transactions = false;
}
