Introduced CargoRepository with tests (failing).

dddsample/src/main/java/se/citerus/dddsample/domain/Cargo.java

 package se.citerus.dddsample.domain;
 
 public class Cargo {
-  private final String trackingId;
+  private final TrackingId trackingId;
   private final Location from;
   private final Location to;
 
-  public Cargo(String trackingId, Location origin, Location finalDestination) {
+  public Cargo(TrackingId trackingId, Location origin, Location finalDestination) {
     this.trackingId = trackingId;
     this.from = origin;
     this.to = finalDestination;
   public Location currentLocation() {
     return null;  //To change body of created methods use File | Settings | File Templates.
   }
+
+  public TrackingId trackingId() {
+    return null;  //To change body of created methods use File | Settings | File Templates.
+  }
 }

dddsample/src/main/java/se/citerus/dddsample/domain/CargoRepository.java

+package se.citerus.dddsample.domain;
+
+
+public interface CargoRepository {
+  Cargo find(TrackingId trackingId);
+}

dddsample/src/main/java/se/citerus/dddsample/domain/CargoRepositoryImpl.java

+package se.citerus.dddsample.domain;
+
+public class CargoRepositoryImpl implements CargoRepository {
+  public Cargo find(TrackingId trackingId) {
+    return null;  //To change body of implemented methods use File | Settings | File Templates.
+  }
+}

dddsample/src/main/java/se/citerus/dddsample/domain/TrackingId.java

+package se.citerus.dddsample.domain;
+
+public class TrackingId {
+  public TrackingId(String s) {
+  }
+}

dddsample/src/test/java/se/citerus/dddsample/domain/CargoRepositoryTest.java

+package se.citerus.dddsample.domain;
+
+import junit.framework.TestCase;
+
+public class CargoRepositoryTest extends TestCase {
+
+  public void testFindByCargoId() {
+
+    CargoRepository repository = new CargoRepositoryImpl();
+    final TrackingId trackingId = new TrackingId("XYZ");
+    Cargo cargo = repository.find(trackingId);
+
+    assertSame(trackingId, cargo.trackingId());
+
+  }
+}

dddsample/src/test/java/se/citerus/dddsample/domain/TrackingScenarioTest.java

   }
 
   private Cargo populateCargo() {
-    final Cargo cargo = new Cargo("XYZ", new Location("SESTO"), new Location("AUMEL"));
+    final Cargo cargo = new Cargo(new TrackingId("XYZ"), new Location("SESTO"), new Location("AUMEL"));
 
     final CarrierMovement stockholmToHamburg =
        new CarrierMovement(new Location("SESTO"), new Location("DEHAM"));