public function testExecuteFirstColumn()
{
$writer_names = $this->connection->selectFirstColumn('writers', 'name', null, 'name');
$this->assertInternalType('array', $writer_names);
$this->assertEquals(['Alexander Pushkin', 'Fyodor Dostoyevsky', 'Leo Tolstoy'], $writer_names);
$writer_birthdays = $this->connection->selectFirstColumn('writers', 'birthday', null, 'name');
$this->assertInternalType('array', $writer_birthdays);
$this->assertEquals(['1799-06-06', '1821-11-11', '1828-09-09'], $writer_birthdays);
}
