public function testGettersSetters()
{
$invoice = new Invoice();
$this->assertTrue($invoice === $invoice->setPriceType(Invoice::PRICE_GROSS));
$this->assertEquals(Invoice::PRICE_GROSS, $invoice->getPriceType());
$this->assertTrue($invoice === $invoice->setCurrency('EUR'));
$this->assertEquals('EUR', $invoice->getCurrency());
$this->assertEquals(2, $invoice->getPrecision());
$this->assertTrue($invoice === $invoice->setCurrency('JPY', 0));
$this->assertEquals('JPY', $invoice->getCurrency());
$this->assertEquals(0, $invoice->getPrecision());
$address = array('imos GmbH', 'Alfons-Feifel-Str. 9', '73037 Göppingen');
$this->assertTrue($invoice === $invoice->setCustomerAddress($address));
$this->assertEquals($address, $invoice->getCustomerAddress());
$this->assertTrue($invoice === $invoice->setCustomerNumber('99999'));
$this->assertEquals('99999', $invoice->getCustomerNumber());
$this->assertTrue($invoice === $invoice->setInvoiceNumber('RE-12345'));
$this->assertEquals('RE-12345', $invoice->getInvoiceNumber());
$this->assertTrue($invoice === $invoice->setInvoiceDate(new DateTime('2016-01-01')));
$this->assertEquals(new DateTime('2016-01-01'), $invoice->getInvoiceDate());
$this->assertTrue($invoice === $invoice->setDueDate(new DateTime('2016-02-01')));
$this->assertEquals(new DateTime('2016-02-01'), $invoice->getDueDate());
$this->assertTrue($invoice === $invoice->setBillingPeriod(DateRange::create('2016-01-01', '2016-02-01')));
$this->assertEquals(DateRange::create('2016-01-01', '2016-02-01'), $invoice->getBillingPeriod());
$this->assertTrue($invoice === $invoice->setCommission('Partner 1'));
$this->assertEquals('Partner 1', $invoice->getCommission());
$this->assertTrue($invoice === $invoice->clearTaxIds());
$this->assertTrue($invoice === $invoice->addTaxId('Ust-ID', 'DE999999999'));
$this->assertTrue($invoice === $invoice->addTaxId('Steuernummer', '12345 / 67890'));
$this->assertEquals(array(array('label' => 'Ust-ID', 'value' => 'DE999999999'), array('label' => 'Steuernummer', 'value' => '12345 / 67890')), $invoice->getTaxIds());
$this->assertTrue($invoice === $invoice->setPaymentTerms('30 days strictly net'));
$this->assertEquals('30 days strictly net', $invoice->getPaymentTerms());
$this->assertTrue($invoice === $invoice->clearExtraInfo());
$this->assertTrue($invoice === $invoice->addExtraInfo('Payable by bank transfer.'));
$this->assertTrue($invoice === $invoice->addExtraInfo('IBAN: DE99 1234 5678 9012 3456 78'));
$this->assertEquals(array('Payable by bank transfer.', 'IBAN: DE99 1234 5678 9012 3456 78'), $invoice->getExtraInfo());
$item1 = new LineItem();
$item2 = new LineItem();
$this->assertTrue($invoice === $invoice->clearLineItems());
$this->assertTrue($invoice === $invoice->addLineItem($item1));
$this->assertTrue($invoice === $invoice->addLineItem($item2));
$result = $invoice->getLineItems();
$this->assertCount(2, $result);
$this->assertTrue($item1 === $result[0]);
$this->assertTrue($item2 === $result[1]);
}