Add tests

tests/DCC/AdministrativeData.Customer.test.ts

@@ -6,7 +6,7 @@
 import { select, toTextArr, toTextContentArr } from "../util";
 import { ContactType, DCCDocument, LocationType } from "../../src";
 
-const base = "//dcc:administrativeData/dcc:customer";
+const base = "/dcc:digitalCalibrationCertificate/dcc:administrativeData/dcc:customer";
 const xpath = {
   customer: {
     name: {
@@ -37,7 +37,7 @@ describe("ContactType", () => {
   beforeEach(async () => {
     ({ dcc, dom } = await xmlEnv.recreateEnv());
     customer = dcc.digitalCalibrationCertificate.administrativeData.customer;
-    location = customer.location;
+    location = customer.location; /* TODO: check iff this variable is used anywhere */
   });
 
   test("should get correct customer name content from XML", () => {