Add ISubscriberFactory implementation and test harness.

Author: walterpinson

src/Core/Domain/Factories/SubscriberFactory.cs

@@ -0,0 +1,14 @@
+namespace CompanyName.Notebook.NoteTaking.Core.Domain.Factories
+{
+    using System;
+    using CompanyName.Notebook.NoteTaking.Core.Domain.Models;
+
+    public class SubscriberFactory : ISubscriberFactory
+    {
+        public ISubscriber Create(string emailAddress)
+        {
+            if (string.IsNullOrEmpty(emailAddress)) throw new ArgumentException("Must have email address to create subscriber.", nameof(emailAddress));
+            return new Subscriber(emailAddress);
+        }
+    }
+}

test/Test.Unit.Core/Domain/Factories/SubscriberFactoryTester.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 SubscriberFactoryTester
+    {
+        [Test]
+        public void CanConstructSubscriberFactory()
+        {
+            // ARRANGE
+
+            // ACT
+            var subjectUnderTest = new SubscriberFactory();
+
+            // ASSERT
+            Assert.That(subjectUnderTest, Is.TypeOf(typeof(SubscriberFactory)));
+            Assert.That(subjectUnderTest, Is.InstanceOf(typeof(ISubscriberFactory)));
+        }
+
+        [Test]
+        public void CanCreateSubscriber()
+        {
+            // ARRANGE
+            var expectedEmailAddress = "mickey.mouse@disney.com";
+            var subjectUnderTest = new SubscriberFactory();
+
+            // ACT
+            var result = subjectUnderTest.Create(expectedEmailAddress);
+
+            // ASSERT
+            Assert.That(result, Is.Not.Null);
+            Assert.That(result, Is.InstanceOf(typeof(ISubscriber)));
+            Assert.That(result.EmailAddress, Is.EqualTo(expectedEmailAddress));
+        }
+
+        [Test]
+        public void CreateThrowsArgumentExceptionWhenEmailNull()
+        {
+            // ARRANGE
+            var expectedExceptionMessage = "Must have email address to create subscriber.\nParameter name: emailAddress";
+            var subjectUnderTest = new SubscriberFactory();
+
+            // ACT
+            // ASSERT
+            var ex = Assert.Throws<ArgumentException>(
+                () => subjectUnderTest.Create(null)
+            );
+            Assert.That(ex.Message, Is.EqualTo(expectedExceptionMessage));
+        }
+    }
+}