Added getIssuerAssignedID() to ZUGFeRDImporter.java

Added Test

libraryBasic/src/main/java/org/mustangproject/ZUGFeRD/ZUGFeRDImporter.java

@@ -290,6 +290,29 @@ public class ZUGFeRDImporter {
 		}
 	}
 
+	/**
+	 * @return the IssuerAssigned ID
+	 */
+	public String getIssuerAssignedID() {
+		try {
+			if (getVersion() == 1) {
+				return extractString("//BuyerOrderReferencedDocument//ID");
+			} else {
+				return extractString("//BuyerOrderReferencedDocument//IssuerAssignedID");
+			}
+		} catch (Exception e) {
+			e.printStackTrace();
+			return "";
+		}
+	}
+
+	/**
+	 * @return the BuyerTradeParty ID
+	 */
+	public String getBuyerTradePartyID() {
+		return extractString("//BuyerTradeParty//ID");
+	}
+
 	/**
 	 * @return the Invoice ID
 	 */

libraryBasic/src/test/java/org/mustangproject/ZUGFeRD/ZF2Test.java

@@ -210,7 +210,7 @@ public class ZF2Test extends MustangReaderTestCase {
 		assertEquals(zi.getInvoiceID(), "RE-20170509/505");
 		assertEquals(zi.getZUGFeRDProfil(), "COMFORT");
 		assertEquals(zi.getInvoiceCurrencyCode(), "EUR");
-
+		assertEquals(zi.getIssuerAssignedID(),"");
 		assertEquals(zi.getHolder(), getOwnOrganisationName());
 		assertEquals(zi.getDocumentCode(),"380");
 		assertEquals(zi.getReference(),"AB321");