Implement AddNote method an associated test.

Author: walterpinson

src/Core/Domain/Models/Category.cs

@@ -2,6 +2,7 @@ namespace CompanyName.Notebook.NoteTaking.Core.Domain.Models
 {
     using System;
     using System.Collections.Generic;
+    using System.Linq;
     using CompanyName.Notebook.NoteTaking.Core.Domain.Factories;
 
     public class Category : ICategory
@@ -45,9 +46,13 @@ public INote AddNote(string text)
             return note;
         }
 
-        public void RemoveNote(Guid Id)
+        public void RemoveNote(Guid id)
         {
-            throw new NotImplementedException();
+            if(Guid.Empty == id) return;
+            if(null == Notes) return;
+            if(Notes.Count < 1) return;
+
+            Notes.Remove(Notes.FirstOrDefault(note => note.Id == id));
         }
 
         public INote RevealNote(Guid id)

test/Test.Unit.Core/Domain/Models/CategoryTester.cs

@@ -148,5 +148,28 @@ public void AddNoteThrowsArgumentExceptionWhenTextNull()
             );
             Assert.That(ex.Message, Is.EqualTo(expectedExceptionMessage));
         }
+
+        [Test]
+        public void CanRemoveNote()
+        {
+            // ARRANGE
+            string expectedName = "Verbose Notes";
+            string expectedNoteText = "This is just a reminder to go to the store.";
+            var expectedId = Guid.NewGuid();
+            var expectedNote = Substitute.For<INote>();
+            var subjectUnderTest = new Category(expectedName, _noteFactory, _subscriberFactory);
+
+            _noteFactory.Create(expectedNoteText).Returns(expectedNote);
+            expectedNote.Id.Returns(expectedId);
+            subjectUnderTest.AddNote(expectedNoteText);
+            Assert.That(subjectUnderTest.Notes.Count, Is.EqualTo(1));
+
+            // ACT
+            subjectUnderTest.RemoveNote(expectedId);
+
+            // ASSERT
+            Assert.That(subjectUnderTest.Notes.Count, Is.EqualTo(0));
+            _noteFactory.Received(1).Create(expectedNoteText);
+        }
     }
 }