public function testAcceptance()
{
$invoiceItems = new InvoiceItems();
$invoiceItems->addItem($bananen = new SimpleInvoiceItem('mehrere Bananen (pauschalpreis)', new Price(2.5, Price::NETTO, 0.19)));
$this->assertEquals(2, $invoiceItems->getNextPosition());
// does not increase
$invoiceItems->addItem($aepfel = new SimpleInvoiceItem('Äpfel (pauschalpreis)', new Price(7.5, Price::BRUTTO, 0.19)));
$this->assertCount(2, $invoiceItems->unwrap());
$this->assertEquals(1, $bananen->getPos());
$this->assertEquals(2, $aepfel->getPos());
$this->assertEquals(array(1 => $bananen, 2 => $aepfel), $invoiceItems->toArray());
}
