From 1c5eac2362422c9d42ef057f38014ea3a8167df3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jochen=20St=C3=A4rk?= <jstaerk@usegroup.de>
Date: Thu, 11 Dec 2025 14:22:46 +0100
Subject: [PATCH] closes #984

---
 .../main/java/org/mustangproject/Product.java |   3 +
 .../ZUGFeRD/IZUGFeRDExportableProduct.java    |   2 +-
 .../ZUGFeRD/ZUGFeRD2PullProvider.java         |   2 +-
 .../model/DocumentCodeTypeConstants.java      |   1 +
 .../ZUGFeRD/VATrelatedTest.java               | 153 ++++++++++++++++++
 .../mustangproject/validator/LibraryTest.java |  38 +++++
 6 files changed, 197 insertions(+), 2 deletions(-)
 create mode 100644 library/src/test/java/org/mustangproject/ZUGFeRD/VATrelatedTest.java

diff --git a/library/src/main/java/org/mustangproject/Product.java b/library/src/main/java/org/mustangproject/Product.java
index 8ca3680b..a472ac4a 100644
--- a/library/src/main/java/org/mustangproject/Product.java
+++ b/library/src/main/java/org/mustangproject/Product.java
@@ -233,6 +233,9 @@ public class Product implements IZUGFeRDExportableProduct {
 	 */
 	public Product setReverseCharge() {
 		isReverseCharge = true;
+		if ((getTaxExemptionReason()==null)||(getTaxExemptionReason().isEmpty())) {
+			setTaxExemptionReason("Reverse charge");
+		}
 		setVATPercent(BigDecimal.ZERO);
 		return this;
 	}
diff --git a/library/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableProduct.java b/library/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableProduct.java
index 6ee5f22e..71402d8b 100644
--- a/library/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableProduct.java
+++ b/library/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableProduct.java
@@ -120,7 +120,7 @@ public interface IZUGFeRDExportableProduct {
 		    return TaxCategoryCodeTypeConstants.INTRACOMMUNITY;// "K"; // within europe
 		} else if (isReverseCharge()) {
 		    return TaxCategoryCodeTypeConstants.REVERSECHARGE;// "AE"; // to out of europe...
-		} else if (getVATPercent().compareTo(BigDecimal.ZERO) == 0) {
+		} else if ((getVATPercent()==null)||(getVATPercent().compareTo(BigDecimal.ZERO) == 0)) {
 		    return TaxCategoryCodeTypeConstants.ZEROTAXPRODUCTS; // "Z"; // zero rated goods
 		} else {
 		    return TaxCategoryCodeTypeConstants.STANDARDRATE;// "S"; // one of the "standard" rates (not
diff --git a/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRD2PullProvider.java b/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRD2PullProvider.java
index cddadf7a..50565ecc 100644
--- a/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRD2PullProvider.java
+++ b/library/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRD2PullProvider.java
@@ -538,7 +538,7 @@ public class ZUGFeRD2PullProvider implements IXMLProvider {
 					xml += "<ram:ExemptionReason>" + XMLTools.encodeXML(currentItem.getProduct().getTaxExemptionReason()) + "</ram:ExemptionReason>";
 				}
 				xml += "<ram:CategoryCode>" + currentItem.getProduct().getTaxCategoryCode() + "</ram:CategoryCode>";
-				if (!currentItem.getProduct().getTaxCategoryCode().equals(TaxCategoryCodeTypeConstants.UNTAXEDSERVICE)) {
+				if ((!currentItem.getProduct().getTaxCategoryCode().equals(TaxCategoryCodeTypeConstants.UNTAXEDSERVICE)) && (!currentItem.getProduct().getTaxCategoryCode().equals(TaxCategoryCodeTypeConstants.ZEROTAXPRODUCTS))) {
 					xml += "<ram:RateApplicablePercent>" + vatFormat(currentItem.getProduct().getVATPercent()) + "</ram:RateApplicablePercent>";
 				}
 				xml += "</ram:ApplicableTradeTax>";
diff --git a/library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentCodeTypeConstants.java b/library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentCodeTypeConstants.java
index 74fac56a..61cfd66a 100644
--- a/library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentCodeTypeConstants.java
+++ b/library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentCodeTypeConstants.java
@@ -23,5 +23,6 @@ public class DocumentCodeTypeConstants {
 	public static final String CREDITNOTE = "381";
 	public static final String DEBITNOTE = "84";
 	public static final String CORRECTEDINVOICE = "384";
+	public static final String SELFBILLING = "389";
 	public static final String PARTIAL_BILLING = "326";
 }
diff --git a/library/src/test/java/org/mustangproject/ZUGFeRD/VATrelatedTest.java b/library/src/test/java/org/mustangproject/ZUGFeRD/VATrelatedTest.java
new file mode 100644
index 00000000..7cd41ead
--- /dev/null
+++ b/library/src/test/java/org/mustangproject/ZUGFeRD/VATrelatedTest.java
@@ -0,0 +1,153 @@
+
+/** **********************************************************************
+ *
+ * Copyright 2019 Jochen Staerk
+ *
+ * Use is subject to license terms.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *********************************************************************** */
+package org.mustangproject.ZUGFeRD;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.FixMethodOrder;
+import org.junit.runners.MethodSorters;
+import org.mustangproject.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.math.BigDecimal;
+import java.nio.charset.StandardCharsets;
+import java.util.Date;
+
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class VATrelatedTest extends ResourceCase  {
+	final String TARGET_PDF_REVERSE = "./target/testout-ReverseCharge.pdf";
+	final String TARGET_PDF_Z = "./target/testout-TaxcodeZ.pdf";
+
+	public void testReverseCharge() {
+
+		String orgname = "Test company";
+		String number = "123";
+		String priceStr = "3.00";
+		BigDecimal price = new BigDecimal(priceStr);
+		try {
+			InputStream SOURCE_PDF = this.getClass().getResourceAsStream("/MustangGnuaccountingBeispielRE-20170509_505blanko.pdf");
+
+			ZUGFeRDExporterFromA1 ze = new ZUGFeRDExporterFromA1();
+			ze.ignorePDFAErrors().load(SOURCE_PDF);
+			ze.setProfile(Profiles.getByName("Extended"));
+
+			ze.setProducer("My Application").setCreator(System.getProperty("user.name")).setZUGFeRDVersion(2).setProfile("extended");
+			//	ze.setTransaction(new Invoice().setDueDate(new Date()).setIssueDate(new Date()).setDeliveryDate(new Date()).setSender(new TradeParty(orgname,"teststr", "55232","teststadt","DE")).setOwnTaxID("4711").setOwnVATID("DE0815").setRecipient(new TradeParty("Franz Müller", "teststr.12", "55232", "Entenhausen", "DE")).setNumber(number)
+			//					.addItem(new Item(new Product("Testprodukt", "", "H84", new BigDecimal(19)), amount, new BigDecimal(1.0)).addAllowance(new Allowance().setPercent(new BigDecimal(50)))));
+
+			Product p=new Product("Testprodukt", "", "H87", new BigDecimal(19));
+			p.setReverseCharge();
+			Invoice i = new Invoice().setDueDate(new Date()).setIssueDate(new Date()).setDeliveryDate(new Date())
+				.setSender(new TradeParty(orgname, "teststr", "55232", "teststadt", "DE").addTaxID("4711").addVATID("DE0815"))
+				.setRecipient(new TradeParty("Franz Müller", "teststr.12", "55232", "Entenhausen", "DE")
+					.setContact(new Contact("contact testname", "123456", "contact.testemail@example.org").setFax("0911623562")).addVATID("DE0915"))
+				.setNumber(number)
+				.addCharge(new Charge(new BigDecimal(1)).setReasonCode("ABK").setReason("AReason").setTaxPercent(new BigDecimal(19)))
+
+				.addItem(new Item(p, price, new BigDecimal(1.0)));
+			ze.setTransaction(i);
+
+
+			String theXML = new String(ze.getProvider().getXML(), StandardCharsets.UTF_8);
+			assertTrue(theXML.contains("<rsm:CrossIndustryInvoice"));
+			ze.export(TARGET_PDF_REVERSE);
+		} catch (IOException e) {
+			fail("IOException should not be raised");
+		}
+
+		try {
+			// now check the contents (like MustangReaderTest)
+			ZUGFeRDImporter zi = new ZUGFeRDImporter(TARGET_PDF_REVERSE);
+			assertEquals("EUR", zi.getInvoiceCurrencyCode());
+			assertTrue(zi.getUTF8().contains("0911623562")); // fax number
+
+			// Reading ZUGFeRD
+			assertEquals("4.19", zi.getAmount());
+			assertEquals(orgname, zi.getHolder());
+			assertEquals(number, zi.getForeignReference());
+			assertEquals(zi.getVersion(), 2);
+		} catch (Exception e) {
+			fail("Exception "+e.getMessage()+" should not be raised");
+		}
+	}
+
+	public void testTaxcodeZ() {
+
+		String orgname = "Test company";
+		String number = "123";
+		String priceStr = "3.00";
+		BigDecimal price = new BigDecimal(priceStr);
+		try {
+			InputStream SOURCE_PDF = this.getClass().getResourceAsStream("/MustangGnuaccountingBeispielRE-20170509_505blanko.pdf");
+
+			ZUGFeRDExporterFromA1 ze = new ZUGFeRDExporterFromA1();
+			ze.ignorePDFAErrors().load(SOURCE_PDF);
+			ze.setProfile(Profiles.getByName("Extended"));
+
+			ze.setProducer("My Application").setCreator(System.getProperty("user.name")).setZUGFeRDVersion(2).setProfile("extended");
+			//	ze.setTransaction(new Invoice().setDueDate(new Date()).setIssueDate(new Date()).setDeliveryDate(new Date()).setSender(new TradeParty(orgname,"teststr", "55232","teststadt","DE")).setOwnTaxID("4711").setOwnVATID("DE0815").setRecipient(new TradeParty("Franz Müller", "teststr.12", "55232", "Entenhausen", "DE")).setNumber(number)
+			//					.addItem(new Item(new Product("Testprodukt", "", "H84", new BigDecimal(19)), amount, new BigDecimal(1.0)).addAllowance(new Allowance().setPercent(new BigDecimal(50)))));
+
+			Product p;
+
+			ObjectMapper mapper = new ObjectMapper();
+			String json="{\n" +
+				"        \"unit\": \"H87\",\n" +
+				"        \"name\": \"Joghurt Banane\",\n" +
+				"        \"description\": \"\",\n" +
+
+				"        \"taxCategoryCode\": \"Z\"\n" +
+				"      }";// 				"        \"vatpercent\": 0,\n" + missing, #979
+			p=mapper.readValue(json, Product.class);
+
+			Invoice i = new Invoice().setDueDate(new Date()).setIssueDate(new Date()).setDeliveryDate(new Date())
+				.setSender(new TradeParty(orgname, "teststr", "55232", "teststadt", "DE").addTaxID("4711").addVATID("DE0815"))
+				.setRecipient(new TradeParty("Franz Müller", "teststr.12", "55232", "Entenhausen", "DE")
+					.setContact(new Contact("contact testname", "123456", "contact.testemail@example.org").setFax("0911623562")))
+				.setNumber(number)
+				.addCharge(new Charge(new BigDecimal(1)).setReasonCode("ABK").setReason("AReason").setTaxPercent(new BigDecimal(19)))
+
+				.addItem(new Item(p, price, new BigDecimal(1.0)));
+			ze.setTransaction(i);
+
+
+			String theXML = new String(ze.getProvider().getXML(), StandardCharsets.UTF_8);
+			assertTrue(theXML.contains("<rsm:CrossIndustryInvoice"));
+			ze.export(TARGET_PDF_Z);
+		} catch (IOException e) {
+			fail("IOException should not be raised");
+		}
+
+		try {
+			// now check the contents (like MustangReaderTest)
+			ZUGFeRDImporter zi = new ZUGFeRDImporter(TARGET_PDF_Z);
+			assertEquals("EUR", zi.getInvoiceCurrencyCode());
+			assertTrue(zi.getUTF8().contains("0911623562")); // fax number
+
+			// Reading ZUGFeRD
+			assertEquals("4.19", zi.getAmount());
+			assertEquals(orgname, zi.getHolder());
+			assertEquals(number, zi.getForeignReference());
+			assertEquals(zi.getVersion(), 2);
+		} catch (Exception e) {
+			fail("Exception should not be raised");
+		}
+	}
+}
diff --git a/validator/src/test/java/org/mustangproject/validator/LibraryTest.java b/validator/src/test/java/org/mustangproject/validator/LibraryTest.java
index 62850db3..8a072a0c 100644
--- a/validator/src/test/java/org/mustangproject/validator/LibraryTest.java
+++ b/validator/src/test/java/org/mustangproject/validator/LibraryTest.java
@@ -112,6 +112,44 @@ public class LibraryTest extends ResourceCase {
 				.isEqualTo("valid");
 
 	}
+
+	public void testLibraryTaxcodeZ() {
+		File tempFile = new File("../library/target/testout-TaxcodeZ.pdf");
+		assertTrue(tempFile.exists());
+		ZUGFeRDValidator zfv = new ZUGFeRDValidator();
+
+		String res = zfv.validate(tempFile.getAbsolutePath());
+
+
+		assertThat(res).valueByXPath("/validation/pdf/summary/@status")
+			.isEqualTo("valid");
+
+		assertThat(res).valueByXPath("/validation/xml/summary/@status")
+			.isEqualTo("valid");
+
+		assertThat(res).valueByXPath("/validation/summary/@status")
+			.isEqualTo("valid");
+
+	}
+	public void testLibraryReverseCharge() {
+		File tempFile = new File("../library/target/testout-ReverseCharge.pdf");
+		assertTrue(tempFile.exists());
+		ZUGFeRDValidator zfv = new ZUGFeRDValidator();
+
+		String res = zfv.validate(tempFile.getAbsolutePath());
+
+
+		assertThat(res).valueByXPath("/validation/pdf/summary/@status")
+			.isEqualTo("valid");
+
+		assertThat(res).valueByXPath("/validation/xml/summary/@status")
+			.isEqualTo("valid");
+
+		assertThat(res).valueByXPath("/validation/summary/@status")
+			.isEqualTo("valid");
+
+	}
+
 	public void testLibraryPushAllowances() {
 		File tempFile = new File("../library/target/testout-ZF2PushChargesAllowances.pdf");
 		assertTrue(tempFile.exists());