diff --git a/Test.cs b/Test.cs
index f34c04f..3998f5f 100644
--- a/Test.cs
+++ b/Test.cs
@@ -6,6 +6,131 @@
 
 namespace EventSourcing.Demo
 {
+    public abstract class AggregateTests<TAggregate> where TAggregate : AggregateRoot
+    {
+        private readonly TAggregate _aggregateRoot;
+
+        protected AggregateTests(TAggregate aggregateRoot)
+        {
+            _aggregateRoot = aggregateRoot;
+        }
+
+        protected void Given(params IEvent[] events)
+        {
+            if (events != null)
+            {
+                _aggregateRoot.Load(events);
+            }
+        }
+
+        protected void When(Action<TAggregate> command)
+        {
+            command(_aggregateRoot);
+        }
+
+        protected void Then<TEvent>(params Action<TEvent>[] conditions)
+        {
+            var events = _aggregateRoot.GetUncommittedEvents();
+            events.Count.ShouldBe(1);
+            var evnt = events.First();
+            evnt.ShouldBeOfType<TEvent>();
+            if (conditions != null)
+            {
+                ((TEvent)evnt).ShouldSatisfyAllConditions(conditions);
+            }
+        }
+
+        protected void Throws<TException>(Action<TAggregate> command, params Action<TException>[] conditions) where TException : Exception
+        {
+            var ex = Should.Throw<TException>(() => command(_aggregateRoot));
+            if (conditions != null)
+            {
+                ex.ShouldSatisfyAllConditions(conditions);
+            }
+        }
+    }
+
+    public class GivenWhenThenTests : AggregateTests<WarehouseProduct>
+    {
+        private readonly Fixture _fixture;
+        private readonly string _sku = "abc123";
+        private readonly int _initialQuantity;
+
+        public GivenWhenThenTests() : base(new WarehouseProduct("abc123"))
+        {
+            _fixture = new Fixture();
+            _fixture.Customizations.Add(new Int32SequenceGenerator());
+            _initialQuantity = (int)_fixture.Create<uint>();
+        }
+
+        [Fact]
+        public void ShipProductShouldRaiseProductShipped()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToShip = _fixture.Create<int>();
+            When(x => x.ShipProduct(quantityToShip));
+
+            Then<ProductShipped>(
+                x => x.Quantity.ShouldBe(quantityToShip),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.EventType.ShouldBe("ProductShipped"));
+        }
+
+        [Fact]
+        public void ShipProductShouldThrowIfNoQuantityOnHand()
+        {
+            Given();
+
+            Throws<InvalidDomainException>(
+                x => x.ShipProduct(1),
+                x => x.Message.ShouldBe("Cannot Ship to a negative Quantity on Hand."));
+        }
+
+        [Fact]
+        public void ReceiveProductShouldRaiseProductReceived()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToReceive = _fixture.Create<int>();
+            When(x => x.ReceiveProduct(quantityToReceive));
+
+            Then<ProductReceived>(
+                x => x.Quantity.ShouldBe(quantityToReceive),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.EventType.ShouldBe("ProductReceived"));
+        }
+
+        [Fact]
+        public void AdjustInventoryShouldRaiseProductAdjusted()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToAdjust = _fixture.Create<int>();
+            var reason = _fixture.Create<string>();
+
+            When(x => x.AdjustInventory(quantityToAdjust, reason));
+
+            Then<InventoryAdjusted>(
+                x => x.Quantity.ShouldBe(quantityToAdjust),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.Reason.ShouldBe(reason),
+                x => x.EventType.ShouldBe("InventoryAdjusted"));
+        }
+
+        [Fact]
+        public void AdjustInventoryShouldThrowIfNoQuantityOnHand()
+        {
+            Given();
+
+            var reason = _fixture.Create<string>();
+
+            Throws<InvalidDomainException>(
+                x => x.AdjustInventory(-1, reason),
+                x => x.Message.ShouldBe("Cannot adjust to a negative Quantity on Hand."));
+        }
+    }
+
     public class ProductTests
     {
         private readonly string _sku;
@@ -45,15 +170,6 @@
         }
 
         [Fact]
-        public void ShipProductShouldUpdateState()
-        {
-            var quantityToShip = _fixture.Create<int>();
-            _sut.ShipProduct(quantityToShip);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity - quantityToShip);
-        }
-
-        [Fact]
         public void ShipProductShouldThrowIfNoQuantityOnHand()
         {
             var ex = Should.Throw<InvalidDomainException>(() => _sut.ShipProduct(_initialQuantity + 1));
@@ -80,15 +196,6 @@
         }
 
         [Fact]
-        public void ReceiveProductShouldUpdateState()
-        {
-            var quantityToReceive = _fixture.Create<int>();
-            _sut.ReceiveProduct(quantityToReceive);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity + quantityToReceive);
-        }
-
-        [Fact]
         public void AdjustInventoryShouldRaiseProductAdjusted()
         {
             var quantityToAdjust = _fixture.Create<int>();
@@ -110,15 +217,6 @@
         }
 
         [Fact]
-        public void AdjustInventoryShouldUpdateState()
-        {
-            var quantityToAdjust = _fixture.Create<int>();
-            _sut.AdjustInventory(quantityToAdjust, string.Empty);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity + quantityToAdjust);
-        }
-
-        [Fact]
         public void AdjustInventoryShouldThrowIfNoQuantityOnHand()
         {
             var ex = Should.Throw<InvalidDomainException>(() => _sut.AdjustInventory((_initialQuantity + 1) * -1, string.Empty));

diff --git a/Test.cs b/Test.cs
index f34c04f..3998f5f 100644
--- a/Test.cs
+++ b/Test.cs
@@ -6,6 +6,131 @@
 
 namespace EventSourcing.Demo
 {
+    public abstract class AggregateTests<TAggregate> where TAggregate : AggregateRoot
+    {
+        private readonly TAggregate _aggregateRoot;
+
+        protected AggregateTests(TAggregate aggregateRoot)
+        {
+            _aggregateRoot = aggregateRoot;
+        }
+
+        protected void Given(params IEvent[] events)
+        {
+            if (events != null)
+            {
+                _aggregateRoot.Load(events);
+            }
+        }
+
+        protected void When(Action<TAggregate> command)
+        {
+            command(_aggregateRoot);
+        }
+
+        protected void Then<TEvent>(params Action<TEvent>[] conditions)
+        {
+            var events = _aggregateRoot.GetUncommittedEvents();
+            events.Count.ShouldBe(1);
+            var evnt = events.First();
+            evnt.ShouldBeOfType<TEvent>();
+            if (conditions != null)
+            {
+                ((TEvent)evnt).ShouldSatisfyAllConditions(conditions);
+            }
+        }
+
+        protected void Throws<TException>(Action<TAggregate> command, params Action<TException>[] conditions) where TException : Exception
+        {
+            var ex = Should.Throw<TException>(() => command(_aggregateRoot));
+            if (conditions != null)
+            {
+                ex.ShouldSatisfyAllConditions(conditions);
+            }
+        }
+    }
+
+    public class GivenWhenThenTests : AggregateTests<WarehouseProduct>
+    {
+        private readonly Fixture _fixture;
+        private readonly string _sku = "abc123";
+        private readonly int _initialQuantity;
+
+        public GivenWhenThenTests() : base(new WarehouseProduct("abc123"))
+        {
+            _fixture = new Fixture();
+            _fixture.Customizations.Add(new Int32SequenceGenerator());
+            _initialQuantity = (int)_fixture.Create<uint>();
+        }
+
+        [Fact]
+        public void ShipProductShouldRaiseProductShipped()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToShip = _fixture.Create<int>();
+            When(x => x.ShipProduct(quantityToShip));
+
+            Then<ProductShipped>(
+                x => x.Quantity.ShouldBe(quantityToShip),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.EventType.ShouldBe("ProductShipped"));
+        }
+
+        [Fact]
+        public void ShipProductShouldThrowIfNoQuantityOnHand()
+        {
+            Given();
+
+            Throws<InvalidDomainException>(
+                x => x.ShipProduct(1),
+                x => x.Message.ShouldBe("Cannot Ship to a negative Quantity on Hand."));
+        }
+
+        [Fact]
+        public void ReceiveProductShouldRaiseProductReceived()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToReceive = _fixture.Create<int>();
+            When(x => x.ReceiveProduct(quantityToReceive));
+
+            Then<ProductReceived>(
+                x => x.Quantity.ShouldBe(quantityToReceive),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.EventType.ShouldBe("ProductReceived"));
+        }
+
+        [Fact]
+        public void AdjustInventoryShouldRaiseProductAdjusted()
+        {
+            Given(new ProductReceived(_sku, _initialQuantity, DateTime.UtcNow));
+
+            var quantityToAdjust = _fixture.Create<int>();
+            var reason = _fixture.Create<string>();
+
+            When(x => x.AdjustInventory(quantityToAdjust, reason));
+
+            Then<InventoryAdjusted>(
+                x => x.Quantity.ShouldBe(quantityToAdjust),
+                x => x.Sku.ShouldBe(_sku),
+                x => x.Reason.ShouldBe(reason),
+                x => x.EventType.ShouldBe("InventoryAdjusted"));
+        }
+
+        [Fact]
+        public void AdjustInventoryShouldThrowIfNoQuantityOnHand()
+        {
+            Given();
+
+            var reason = _fixture.Create<string>();
+
+            Throws<InvalidDomainException>(
+                x => x.AdjustInventory(-1, reason),
+                x => x.Message.ShouldBe("Cannot adjust to a negative Quantity on Hand."));
+        }
+    }
+
     public class ProductTests
     {
         private readonly string _sku;
@@ -45,15 +170,6 @@
         }
 
         [Fact]
-        public void ShipProductShouldUpdateState()
-        {
-            var quantityToShip = _fixture.Create<int>();
-            _sut.ShipProduct(quantityToShip);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity - quantityToShip);
-        }
-
-        [Fact]
         public void ShipProductShouldThrowIfNoQuantityOnHand()
         {
             var ex = Should.Throw<InvalidDomainException>(() => _sut.ShipProduct(_initialQuantity + 1));
@@ -80,15 +196,6 @@
         }
 
         [Fact]
-        public void ReceiveProductShouldUpdateState()
-        {
-            var quantityToReceive = _fixture.Create<int>();
-            _sut.ReceiveProduct(quantityToReceive);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity + quantityToReceive);
-        }
-
-        [Fact]
         public void AdjustInventoryShouldRaiseProductAdjusted()
         {
             var quantityToAdjust = _fixture.Create<int>();
@@ -110,15 +217,6 @@
         }
 
         [Fact]
-        public void AdjustInventoryShouldUpdateState()
-        {
-            var quantityToAdjust = _fixture.Create<int>();
-            _sut.AdjustInventory(quantityToAdjust, string.Empty);
-
-            _sut.GetQuantityOnHand().ShouldBe(_initialQuantity + quantityToAdjust);
-        }
-
-        [Fact]
         public void AdjustInventoryShouldThrowIfNoQuantityOnHand()
         {
             var ex = Should.Throw<InvalidDomainException>(() => _sut.AdjustInventory((_initialQuantity + 1) * -1, string.Empty));
diff --git a/WarehouseProduct.cs b/WarehouseProduct.cs
index 29de5a4..69dacd7 100644
--- a/WarehouseProduct.cs
+++ b/WarehouseProduct.cs
@@ -26,6 +26,8 @@
         {
             _uncommittedEvents.Add(evnt);
         }
+
+        public abstract void Load(IEnumerable<IEvent> events);
     }
 
     public class WarehouseProduct : AggregateRoot
@@ -39,13 +41,18 @@
             Sku = sku;
         }
 
+        public override void Load(IEnumerable<IEvent> events)
+        {
+            foreach (var evnt in events)
+            {
+                Apply(evnt as dynamic);
+            }
+        }
+
         public static WarehouseProduct Load(string sku, IEnumerable<IEvent> events)
         {
             var warehouseProduct = new WarehouseProduct(sku);
-            foreach (var evnt in events)
-            {
-                warehouseProduct.Apply(evnt as dynamic);
-            }
+            warehouseProduct.Load(events);
             return warehouseProduct;
         }
 
@@ -107,6 +114,7 @@
         {
             return _warehouseProductState.QuantityOnHand;
         }
+
     }
 
     public class InvalidDomainException : Exception