public function testAssemble()
{
$clause = new OrderByClause();
$clause->addField((new FieldExpression())->setField('first'));
$this->assertEquals('ORDER BY first', QueryAssembler::stringify($clause));
$clause->clearFields();
$clause->addField((new FieldExpression())->setField('first'), 'ASC');
$this->assertEquals('ORDER BY first ASC', QueryAssembler::stringify($clause));
$clause->clearFields();
$clause->addField((new FieldExpression())->setField('first'), 'DESC');
$this->assertEquals('ORDER BY first DESC', QueryAssembler::stringify($clause));
$clause->addField((new FieldExpression())->setField('second'), 'ASC');
$this->assertEquals('ORDER BY first DESC, second ASC', QueryAssembler::stringify($clause));
$clause->addField('third', 'DESC');
$this->assertEquals('ORDER BY first DESC, second ASC, third DESC', QueryAssembler::stringify($clause));
$clause->addField(CustomSelectExpression::create('DATE(`test`)'));
$this->assertEquals('ORDER BY first DESC, second ASC, third DESC, DATE(`test`)', QueryAssembler::stringify($clause));
}
