introduce delegate to trackingNumber at Shipment

Author: kaiosilveira

src/caller.js

@@ -6,6 +6,6 @@ const trackingInfo = new TrackingInformation();
 aShipment.trackingInformation = trackingInfo;
 
 aShipment.shippingCompany = 'DHL';
-aShipment.trackingInformation.trackingNumber = '1234567890';
+aShipment.trackingNumber = '1234567890';
 
 console.log(aShipment.trackingInfo);

src/shipment/index.js

@@ -14,4 +14,8 @@ export class Shipment {
   set shippingCompany(arg) {
     this._trackingInformation.shippingCompany = arg;
   }
+
+  set trackingNumber(arg) {
+    this._trackingInformation.trackingNumber = arg;
+  }
 }

src/shipment/index.test.js

@@ -8,7 +8,7 @@ describe('Shipment', () => {
     shipment.trackingInformation = trackingInfo;
 
     shipment.shippingCompany = 'DHL';
-    shipment.trackingInformation.trackingNumber = '1234567890';
+    shipment.trackingNumber = '1234567890';
 
     expect(shipment.trackingInfo).toEqual('DHL: 1234567890');
   });