Add NoteFactory implementation and the corresponding test harness.

Author: walterpinson

src/Core/Domain/Factories/NoteFactory.cs

@@ -0,0 +1,14 @@
+namespace CompanyName.Notebook.NoteTaking.Core.Domain.Factories
+{
+    using System;
+    using CompanyName.Notebook.NoteTaking.Core.Domain.Models;
+
+    public class NoteFactory : INoteFactory
+    {
+        public INote Create(string text)
+        {
+            if (string.IsNullOrEmpty(text)) throw new ArgumentException("Must have text to create note.", nameof(text));
+            return new Note(text);
+        }
+    }
+}

test/Test.Unit.Core/Domain/Factories/NoteFactoryTester.cs

@@ -0,0 +1,56 @@
+namespace Test.Unit.Core.Domain.Factories
+{
+    using System;
+    using CompanyName.Notebook.NoteTaking.Core.Domain.Factories;
+    using CompanyName.Notebook.NoteTaking.Core.Domain.Models;
+    using NSubstitute;
+    using NUnit.Framework;
+
+    [TestFixture]
+    public class NoteFactoryTester
+    {
+        [Test]
+        public void CanConstructNoteFactory()
+        {
+            // ARRANGE
+
+            // ACT
+            var subjectUnderTest = new NoteFactory();
+
+            // ASSERT
+            Assert.That(subjectUnderTest, Is.TypeOf(typeof(NoteFactory)));
+            Assert.That(subjectUnderTest, Is.InstanceOf(typeof(INoteFactory)));
+        }
+
+        [Test]
+        public void CanCreateNote()
+        {
+            // ARRANGE
+            var expectedNoteText = "This is just a reminder to go to the store.";
+            var subjectUnderTest = new NoteFactory();
+
+            // ACT
+            var result = subjectUnderTest.Create(expectedNoteText);
+
+            // ASSERT
+            Assert.That(result, Is.Not.Null);
+            Assert.That(result, Is.InstanceOf(typeof(INote)));
+            Assert.That(result.Text, Is.EqualTo(expectedNoteText));
+        }
+
+        [Test]
+        public void CreateThrowsArgumentExceptionWhenTextNull()
+        {
+            // ARRANGE
+            var expectedExceptionMessage = "Must have text to create note.\nParameter name: text";
+            var subjectUnderTest = new NoteFactory();
+
+            // ACT
+            // ASSERT
+            var ex = Assert.Throws<ArgumentException>(
+                () => subjectUnderTest.Create(null)
+            );
+            Assert.That(ex.Message, Is.EqualTo(expectedExceptionMessage));
+        }
+    }
+}