--- a/SilverlightValidation/SilverlightValidation.Tests/ViewModels/UserViewModelTests.cs	Sat May 05 13:29:56 2012 +0100
+++ b/SilverlightValidation/SilverlightValidation.Tests/ViewModels/UserViewModelTests.cs	Sat May 05 16:39:00 2012 +0100
@@ -1,14 +1,42 @@
-using NUnit.Framework;
+using System;
+using NUnit.Framework;
+using SilverlightValidation.Models;
+using SilverlightValidation.Validators;
+using SilverlightValidation.ViewModels;
 
 namespace SilverlightValidation.Tests.ViewModels
 {
     [TestFixture]
     class UserViewModelTests
     {
+        #region constructor tests
+
         [Test]
-        public void Given_When_Then()
+        public void Constructor_WhenTwoNulls_ThenArgumentNullExceptionForModel()
+        {
+            Assert.Throws<ArgumentNullException>(() => new UserViewModel(null, null), "model");
+        }
+
+        [Test]
+        public void Constructor_WhenFirstParameterIsNull_ThenArgumentNullExceptionForModel()
         {
-            Assert.True(true);
+            Assert.Throws<ArgumentNullException>(() => new UserViewModel(null, new UserModelValidator()), "model");
+        }
+
+        [Test]
+        public void Constructor_WhenSecondParameterIsNull_ThenArgumentNullExceptionForValidator()
+        {
+            Assert.Throws<ArgumentNullException>(() => new UserViewModel(new UserModel(), null), "validator");
         }
+
+        [Test]
+        public void DateOfBirth_WhenUpdated_ThenFiresPropertyChangeEvent()
+        {
+            var vm = new UserViewModel(new UserModel(), new UserModelValidator());
+            var tester = new NotifyPropertyChangedTester(vm);
+            //tester.AssertChange();
+        }
+
+        #endregion
     }
 }