diff --git a/PoweredSoft.DynamicQuery.Test/AggregateTests.cs b/PoweredSoft.DynamicQuery.Test/AggregateTests.cs
new file mode 100644
index 0000000..ae68e77
--- /dev/null
+++ b/PoweredSoft.DynamicQuery.Test/AggregateTests.cs
@@ -0,0 +1,116 @@
+using PoweredSoft.DynamicQuery.Core;
+using PoweredSoft.DynamicQuery.Test.Mock;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Xunit;
+
+namespace PoweredSoft.DynamicQuery.Test
+{
+    
+    public class AggregateTests
+    {
+        [Fact]
+        public void WithoutGrouping()
+        {
+            MockContextFactory.SeedAndTestContextFor("AggregateTests_WithoutGrouping", TestSeeders.SimpleSeedScenario, ctx =>
+            {
+                var shouldResult = ctx.OrderItems
+                    .GroupBy(t => true)
+                    .Select(t => new
+                    {
+                        Count = t.Count(),
+                        ItemQuantityAverage = t.Average(t2 => t2.Quantity),
+                        ItemQuantitySum = t.Sum(t2 => t2.Quantity),
+                        AvgOfPrice = t.Average(t2 => t2.PriceAtTheTime)
+                    })
+                    .First();
+
+                // query handler that is empty should be the same as running to list.
+                var criteria = new QueryCriteria()
+                {
+                    Aggregates = new List<Core.IAggregate>
+                    {
+                        new Aggregate { Type = AggregateType.Count },
+                        new Aggregate { Type = AggregateType.Avg, Path = "Quantity" },
+                        new Aggregate { Type = AggregateType.Sum, Path = "Quantity" },
+                        new Aggregate { Type = AggregateType.Avg, Path = "PriceAtTheTime"}
+                    }
+                };
+
+                var queryHandler = new QueryHandler();
+                var result = queryHandler.Execute(ctx.OrderItems, criteria);
+
+                var aggCount = result.Aggregates.First(t => t.Type == AggregateType.Count);
+                var aggItemQuantityAverage  = result.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "Quantity");
+                var aggItemQuantitySum = result.Aggregates.First(t => t.Type == AggregateType.Sum && t.Path == "Quantity");
+                var aggAvgOfPrice = result.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "PriceAtTheTime");
+                Assert.Equal(shouldResult.Count, aggCount.Value);
+                Assert.Equal(shouldResult.ItemQuantityAverage, aggItemQuantityAverage.Value);
+                Assert.Equal(shouldResult.ItemQuantitySum, aggItemQuantitySum.Value);
+                Assert.Equal(shouldResult.AvgOfPrice, aggAvgOfPrice.Value);
+            });
+        }
+
+        [Fact]
+        public void WithGrouping()
+        {
+            MockContextFactory.SeedAndTestContextFor("AggregateTests_WithGrouping", TestSeeders.SimpleSeedScenario, ctx =>
+            {
+                var shouldResults = ctx.OrderItems
+                    .GroupBy(t => t.Order.CustomerId)
+                    .Select(t => new
+                    {
+                        GroupValue = t.Key,
+                        Count = t.Count(),
+                        ItemQuantityAverage = t.Average(t2 => t2.Quantity),
+                        ItemQuantitySum = t.Sum(t2 => t2.Quantity),
+                        AvgOfPrice = t.Average(t2 => t2.PriceAtTheTime)
+                    })
+                    .ToList();
+
+                // query handler that is empty should be the same as running to list.
+                var criteria = new QueryCriteria()
+                {
+                    Groups = new List<IGroup>
+                    {
+                        new Group { Path = "Order.CustomerId" }
+                    },
+                    Aggregates = new List<Core.IAggregate>
+                    {
+                        new Aggregate { Type = AggregateType.Count },
+                        new Aggregate { Type = AggregateType.Avg, Path = "Quantity" },
+                        new Aggregate { Type = AggregateType.Sum, Path = "Quantity" },
+                        new Aggregate { Type = AggregateType.Avg, Path = "PriceAtTheTime"}
+                    }
+                };
+
+                var queryHandler = new QueryHandler();
+                var result = queryHandler.Execute(ctx.OrderItems, criteria);
+                var groups = result.Data.Cast<IGroupQueryResult>().ToList();
+
+                // validate group and aggregates of groups.
+                Assert.Equal(groups.Count, shouldResults.Count);
+                Assert.All(groups, g =>
+                {
+                    var index = groups.IndexOf(g);
+                    var shouldResult = shouldResults[index];
+
+                    // validate the group value.
+                    Assert.Equal(g.GroupValue, shouldResult.GroupValue);
+
+                    // validate the group aggregates.
+                    var aggCount = g.Aggregates.First(t => t.Type == AggregateType.Count);
+                    var aggItemQuantityAverage = g.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "Quantity");
+                    var aggItemQuantitySum = g.Aggregates.First(t => t.Type == AggregateType.Sum && t.Path == "Quantity");
+                    var aggAvgOfPrice = g.Aggregates.First(t => t.Type == AggregateType.Avg && t.Path == "PriceAtTheTime");
+                    Assert.Equal(shouldResult.Count, aggCount.Value);
+                    Assert.Equal(shouldResult.ItemQuantityAverage, aggItemQuantityAverage.Value);
+                    Assert.Equal(shouldResult.ItemQuantitySum, aggItemQuantitySum.Value);
+                    Assert.Equal(shouldResult.AvgOfPrice, aggAvgOfPrice.Value);
+                });
+            });
+        }
+    }
+}
diff --git a/README.md b/README.md
index 9d4cdb6..cfc18aa 100644
--- a/README.md
+++ b/README.md
@@ -20,13 +20,13 @@ Criteria must implement the following interfaces
 Object           | Interface                                                                | Implementation                                                                | Example                                                              | Description
 -----------------|--------------------------------------------------------------------------|-------------------------------------------------------------------------------|----------------------------------------------------------------------|--------------------------------------------
 Query Criteria   | [interface](../master/PoweredSoft.DynamicQuery.Core/IQueryCriteria.cs)   | [default implementation](../master/PoweredSoft.DynamicQuery/QueryCriteria.cs) | [test](../master/PoweredSoft.DynamicQuery.Test/CriteriaTests.cs#L13) | Wraps the query parameters
-Paging          | [interface](../master/PoweredSoft.DynamicQuery.Core/IQueryCriteria.cs)   | [default implementation](../master/PoweredSoft.DynamicQuery/QueryCriteria.cs) | [test](../master/PoweredSoft.DynamicQuery.Test/CriteriaTests.cs#L29) | Paging support
+Paging           | [interface](../master/PoweredSoft.DynamicQuery.Core/IQueryCriteria.cs)   | [default implementation](../master/PoweredSoft.DynamicQuery/QueryCriteria.cs) | [test](../master/PoweredSoft.DynamicQuery.Test/CriteriaTests.cs#L29) | Paging support
 Filter           | [interface](../master/PoweredSoft.DynamicQuery.Core/IFilter.cs)          | [default implementation](../master/PoweredSoft.DynamicQuery/Filter.cs)        | [test](../master/PoweredSoft.DynamicQuery.Test/FilterTests.cs#L22)   | Represent a filter to be executed
 Simple Filter    | [interface](../master/PoweredSoft.DynamicQuery.Core/ISimpleFilter.cs)    | [default implementation](../master/PoweredSoft.DynamicQuery/Filter.cs)        | [test](../master/PoweredSoft.DynamicQuery.Test/FilterTests.cs#L40)   | Represent a simple filter to be executed
 Composite Filter | [interface](../master/PoweredSoft.DynamicQuery.Core/ICompositeFilter.cs) | [default implementation](../master/PoweredSoft.DynamicQuery/Filter.cs)        | [test](../master/PoweredSoft.DynamicQuery.Test/FilterTests.cs#L68)   | Represent a composite filter to be executed
 Sort             | [interface](../master/PoweredSoft.DynamicQuery.Core/ISort.cs)            | [default implementation](../master/PoweredSoft.DynamicQuery/Sort.cs)          | [test](../master/PoweredSoft.DynamicQuery.Test/SortTests.cs#L15)     | Represent a sort to be executed
 Group            | [interface](../master/PoweredSoft.DynamicQuery.Core/IGroup.cs)           | [default implementation](../master/PoweredSoft.DynamicQuery/Group.cs)         | [test](../master/PoweredSoft.DynamicQuery.Test/GroupTests.cs)        | Represent a group to be executed
-Aggregate        | [interface](../master/PoweredSoft.DynamicQuery.Core/IAggregate.cs)       | [default implementation](../master/PoweredSoft.DynamicQuery/Aggregate.cs)     | [test](../master/PoweredSoft.DynamicQuery.Test/TBT.md)               | Represent an aggregate to be executed
+Aggregate        | [interface](../master/PoweredSoft.DynamicQuery.Core/IAggregate.cs)       | [default implementation](../master/PoweredSoft.DynamicQuery/Aggregate.cs)     | [test](../master/PoweredSoft.DynamicQuery.Test/AggregateTests.cs)    | Represent an aggregate to be executed
 
 ### Sample