diff --git a/lib/ProductList/Client.js b/lib/ProductList/Client.js
index 275ffa3..af241b2 100644
--- a/lib/ProductList/Client.js
+++ b/lib/ProductList/Client.js
@@ -25,7 +25,7 @@ class Client {
    * @param {string} [client.id] - The dedicated id of the account if different
    *   from the username but in caps <MANDANTID>
    */
-  constructor({ username, password, id = null }) {
+  constructor({ username, password, id = null } = {}) {
     if (!username || !password) {
       throw new Error(errors.usage.missingClientCredentials);
     }
diff --git a/lib/ProductList/Product.js b/lib/ProductList/Product.js
index c816642..624650d 100644
--- a/lib/ProductList/Product.js
+++ b/lib/ProductList/Product.js
@@ -22,7 +22,9 @@ class Product {
     /** @type {number[]} - The weight range in grams. */
     this._weight = [];
 
-    this._readData(data);
+    if (data) {
+      this._readData(data);
+    }
   }
 
   /**
@@ -55,7 +57,7 @@ class Product {
     return !!this._id;
   }
 
-  _readData(data) {
+  _readData(data = {}) {
     if (data.hasOwnProperty('extendedIdentifier')) {
       this._id = +data.extendedIdentifier.externIdentifier.attributes.id;
       this._name = data.extendedIdentifier.externIdentifier.attributes.name;
diff --git a/lib/errors.js b/lib/errors.js
index 7e4c2b5..bf73ecf 100644
--- a/lib/errors.js
+++ b/lib/errors.js
@@ -22,7 +22,7 @@ module.exports = {
     invalidCountryCode: '3002: Invalid country code for address given: ',
     missingAddressBindings: '3003: Please add receiver and sender to address binding!',
     missingPartnerCredentials: '3004: The api requires valid partner credentials including the id and the secret!',
-    missingPositionParameters: '3005: A position requires at least the productCode and a voucherLayout!',
+    missingPositionParameters: '3005: A position requires at least the product or productCode and a voucherLayout!',
     invalidLayoutZone: '3006: Invalid voucher layout given: ',
     missingProductClients: '3007: The product client credentials are required to make use of the product list. Please add credentials with internetmarke.enableProductList!',
     missingClientCredentials: '3008: The api requires valid client credentials including the username and password!'
diff --git a/test/Order/Order.test.js b/test/Order/Order.test.js
index 750351c..a37edc6 100644
--- a/test/Order/Order.test.js
+++ b/test/Order/Order.test.js
@@ -29,15 +29,15 @@ describe('Order', () => {
 
       const product = {
         getId: sinon.stub().returns(1),
-        getPrice: sinon.stub().returned(70)
+        getPrice: sinon.stub().returns(70)
       };
 
-      order.addPosition({ product });
+      order.addPosition({ product, voucherLayout: 'FrankingZone' });
 
       product.getId.calledOnce.should.be.true();
       product.getPrice.calledOnce.should.be.true();
 
-      order._positions.length.should.have.length(1);
+      order._positions.should.have.length(1);
     });
   });
 
diff --git a/test/ProductList/Client.test.js b/test/ProductList/Client.test.js
index ef2e7cc..dbd95a6 100644
--- a/test/ProductList/Client.test.js
+++ b/test/ProductList/Client.test.js
@@ -24,7 +24,7 @@ describe('Client', () => {
     client.getId().should.equal(args.id);
   });
   
-  it('should generate the client id if not given', () {
+  it('should generate the client id if not given', () => {
     const credentials = {
       username: 'myusername',
       password: '*****'
@@ -32,6 +32,6 @@ describe('Client', () => {
 
     const client = new Client(credentials);
 
-    client.getId().shoul.equal(credentials.username.toUpperCase());
+    client.getId().should.equal(credentials.username.toUpperCase());
   });
 });
diff --git a/test/ProductList/Product.test.js b/test/ProductList/Product.test.js
index 2d755a9..119cbcc 100644
--- a/test/ProductList/Product.test.js
+++ b/test/ProductList/Product.test.js
@@ -26,7 +26,7 @@ describe('Product', () => {
         product.getId().should.equal(data.gen.id);
         product.getPrice().should.equal(data.gen.price);
         product.getName().should.equal(data.gen.name);
-        product._dimensions.should.have.properties('length', 'weight', 'height');
+        product._dimensions.should.have.properties('length', 'width', 'height');
         product._dimensions.length.should.have.length(2);
         product._weight.should.have.length(2);
         product._ppl.should.equal(data.gen.ppl);