Fix invoice calculation if rounding amount is present

library/src/test/java/org/mustangproject/ZUGFeRD/ZF2ZInvoiceImporterTest.java

@@ -466,4 +466,12 @@ public class ZF2ZInvoiceImporterTest extends ResourceCase {
 		assertFalse(invoice.getZFItems()[0].getNotes() == null);
 		assertEquals(1, invoice.getZFItems()[0].getNotes().length);
 	}
+
+	@Test
+	public void testImportXRechnungWithoutCalculationErrors() throws FileNotFoundException, XPathExpressionException, ParseException {
+		File inputFile = getResourceAsFile("cii/02.03a-INVOICE_uncefact.xml");
+		ZUGFeRDInvoiceImporter zii = new ZUGFeRDInvoiceImporter(new FileInputStream(inputFile));
+
+		assertEquals("0", zii.importedInvoice.getDuePayable().toPlainString());
+	}
 }