UpdateName only sends events if there is a change.

Add unit tests

Author: ardalis

src/Clean.Architecture.Core/ContributorAggregate/Contributor.cs

@@ -16,6 +16,7 @@ public Contributor UpdatePhoneNumber(PhoneNumber newPhoneNumber)
 
   public Contributor UpdateName(ContributorName newName)
   {
+    if (Name == newName) return this;
     Name = newName;
     RegisterDomainEvent(new ContributorNameUpdatedEvent(this));
     return this;

tests/Clean.Architecture.UnitTests/Core/ContributorAggregate/ContributorUpdateName.cs

@@ -0,0 +1,40 @@
+using Clean.Architecture.Core.ContributorAggregate.Events;
+
+namespace Clean.Architecture.UnitTests.Core.ContributorAggregate;
+
+public class ContributorUpdateName
+{
+  private readonly ContributorName _initialName = ContributorName.From("initial name");
+  private readonly ContributorName _newName = ContributorName.From("new name");
+  private Contributor? _testContributor;
+  private Contributor CreateContributor()
+  {
+    return new Contributor(_initialName);
+  }
+
+  [Fact]
+  public void UpdatesName()
+  {
+    _testContributor = CreateContributor();
+    _testContributor.UpdateName(_newName);
+    _testContributor.Name.ShouldBe(_newName);
+  }
+
+  [Fact]
+  public void RegistersDomainEvent()
+  {
+    _testContributor = CreateContributor();
+    _testContributor.UpdateName(_newName);
+    _testContributor.DomainEvents.Count.ShouldBe(1);
+    _testContributor.DomainEvents.First().ShouldBeOfType<ContributorNameUpdatedEvent>();
+  }
+
+  [Fact]
+  public void DoesNotRegisterDomainEventGivenCurrentName()
+  {
+    _testContributor = CreateContributor();
+    _testContributor.UpdateName(_initialName);
+    _testContributor.DomainEvents.Count.ShouldBe(0);
+  }
+
+}