diff --git a/MonoStockPortfolio.Tests/Framework/ValidationTests.cs b/MonoStockPortfolio.Tests/Framework/ValidationTests.cs
deleted file mode 100644
index 7781c94..0000000
--- a/MonoStockPortfolio.Tests/Framework/ValidationTests.cs
+++ /dev/null
@@ -1,28 +0,0 @@
-using System.Collections.Generic;
-using System.Linq;
-using Machine.Specifications;
-using MonoStockPortfolio.Activites.EditPortfolioScreen;
-using MonoStockPortfolio.Framework;
-
-namespace MonoStockPortfolio.Tests.Framework
-{
-    public class ValidationTests
-    {
-        static FormValidator _validator;
-        static IEnumerable<string> _errors;
-
-        Establish context = () =>
-                                {
-                                    _validator = new FormValidator();
-                                };
-
-        Because of = () =>
-                         {
-                             _validator.AddRequired(() => "", "This is required");
-                             _errors = _validator.Apply();
-                         };
-
-        It should_return_1_error_message = () =>
-            _errors.Count().ShouldEqual(1);
-    }
-}
\ No newline at end of file
diff --git a/MonoStockPortfolio.Tests/Framework/When_validating_forms_with_validation_errors.cs b/MonoStockPortfolio.Tests/Framework/When_validating_forms_with_validation_errors.cs
new file mode 100644
index 0000000..b7ee5ac
--- /dev/null
+++ b/MonoStockPortfolio.Tests/Framework/When_validating_forms_with_validation_errors.cs
@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+using System.Linq;
+using Machine.Specifications;
+using MonoStockPortfolio.Framework;
+
+namespace MonoStockPortfolio.Tests.Framework
+{
+    public class When_validating_forms_with_validation_errors
+    {
+        static FormValidator _validator;
+        static IEnumerable<string> _errors;
+
+        Establish context = () =>
+                                {
+                                    _validator = new FormValidator();
+                                };
+
+        Because of = () =>
+                         {
+                             _validator.AddRequired(() => "", "This is required");
+                             _validator.AddValidDecimal(() => "not a decimal", "Decimal required");
+                             _validator.AddValidPositiveDecimal(() => "-18.9", "Positive decimal required");
+                             _validator.AddValidation(() => "arbitrary error!");
+                             _errors = _validator.Apply();
+                         };
+
+        It should_return_1_error_message = () =>
+            _errors.Count().ShouldEqual(4);
+        It should_have_a_required_message = () =>
+            _errors.Any(e => e == "This is required").ShouldBeTrue();
+        It should_have_a_valid_decimal_message = () =>
+            _errors.Any(e => e == "Decimal required").ShouldBeTrue();
+        It should_have_a_valid_positive_decimal_message = () =>
+            _errors.Any(e => e == "Positive decimal required").ShouldBeTrue();
+        It should_have_an_arbitrary_message = () =>
+            _errors.Any(e => e == "arbitrary error!").ShouldBeTrue();
+    }
+}
\ No newline at end of file
diff --git a/MonoStockPortfolio.Tests/MonoStockPortfolio.Tests.csproj b/MonoStockPortfolio.Tests/MonoStockPortfolio.Tests.csproj
index 17bf125..0a39d47 100644
--- a/MonoStockPortfolio.Tests/MonoStockPortfolio.Tests.csproj
+++ b/MonoStockPortfolio.Tests/MonoStockPortfolio.Tests.csproj
@@ -21,6 +21,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <NoWarn>169</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -56,19 +57,15 @@
     <Reference Include="Telerik.JustMock.Silverlight">
       <HintPath>..\libs\Telerik.JustMock.Silverlight.dll</HintPath>
     </Reference>
-    <Reference Include="xunit, Version=1.6.1.1521, Culture=neutral, PublicKeyToken=8d05b1bb7a6fdb6c, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\libs\xunit.dll</HintPath>
-    </Reference>
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="Framework\ValidationTests.cs" />
+    <Compile Include="Framework\When_validating_forms_with_validation_errors.cs" />
     <Compile Include="Presenters\EditPortfolioTests.cs" />
     <Compile Include="Presenters\EditPositionTests.cs" />
     <Compile Include="Presenters\MainPresenterTests.cs" />
     <Compile Include="Presenters\PortfolioPresenterTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="YahooStockDataProviderTests.cs" />
+    <Compile Include="Services\YahooStockDataServiceTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\MonoStockPortfolio.Core\MonoStockPortfolio.Core.csproj">
diff --git a/MonoStockPortfolio.Tests/Presenters/EditPortfolioTests.cs b/MonoStockPortfolio.Tests/Presenters/EditPortfolioTests.cs
index b5b468e..8e0611c 100644
--- a/MonoStockPortfolio.Tests/Presenters/EditPortfolioTests.cs
+++ b/MonoStockPortfolio.Tests/Presenters/EditPortfolioTests.cs
@@ -5,6 +5,7 @@ using MonoStockPortfolio.Activites.EditPortfolioScreen;
 using MonoStockPortfolio.Core.PortfolioRepositories;
 using MonoStockPortfolio.Entities;
 using Telerik.JustMock;
+using Telerik.JustMock.Helpers;
 
 namespace MonoStockPortfolio.Tests.Presenters
 {
diff --git a/MonoStockPortfolio.Tests/Presenters/EditPositionTests.cs b/MonoStockPortfolio.Tests/Presenters/EditPositionTests.cs
index 38ed9e9..d496a71 100644
--- a/MonoStockPortfolio.Tests/Presenters/EditPositionTests.cs
+++ b/MonoStockPortfolio.Tests/Presenters/EditPositionTests.cs
@@ -8,6 +8,7 @@ using MonoStockPortfolio.Core.PortfolioRepositories;
 using MonoStockPortfolio.Core.StockData;
 using MonoStockPortfolio.Entities;
 using Telerik.JustMock;
+using Telerik.JustMock.Helpers;
 
 namespace MonoStockPortfolio.Tests.Presenters
 {
diff --git a/MonoStockPortfolio.Tests/Presenters/MainPresenterTests.cs b/MonoStockPortfolio.Tests/Presenters/MainPresenterTests.cs
index 66a7629..8887acd 100644
--- a/MonoStockPortfolio.Tests/Presenters/MainPresenterTests.cs
+++ b/MonoStockPortfolio.Tests/Presenters/MainPresenterTests.cs
@@ -5,7 +5,7 @@ using MonoStockPortfolio.Activites.MainScreen;
 using MonoStockPortfolio.Core.PortfolioRepositories;
 using MonoStockPortfolio.Entities;
 using Telerik.JustMock;
-using Xunit;
+using Telerik.JustMock.Helpers;
 
 namespace MonoStockPortfolio.Tests.Activities
 {
diff --git a/MonoStockPortfolio.Tests/Presenters/PortfolioPresenterTests.cs b/MonoStockPortfolio.Tests/Presenters/PortfolioPresenterTests.cs
index 47268b7..b92e4ee 100644
--- a/MonoStockPortfolio.Tests/Presenters/PortfolioPresenterTests.cs
+++ b/MonoStockPortfolio.Tests/Presenters/PortfolioPresenterTests.cs
@@ -8,6 +8,7 @@ using MonoStockPortfolio.Core.Services;
 using MonoStockPortfolio.Entities;
 using MonoStockPortfolio.Framework;
 using Telerik.JustMock;
+using Telerik.JustMock.Helpers;
 
 namespace MonoStockPortfolio.Tests.Presenters
 {
diff --git a/MonoStockPortfolio.Tests/Services/YahooStockDataServiceTests.cs b/MonoStockPortfolio.Tests/Services/YahooStockDataServiceTests.cs
new file mode 100644
index 0000000..331cb5c
--- /dev/null
+++ b/MonoStockPortfolio.Tests/Services/YahooStockDataServiceTests.cs
@@ -0,0 +1,56 @@
+using System.Collections.Generic;
+using System.Linq;
+using Machine.Specifications;
+using Machine.Specifications.Runner.Impl;
+using MonoStockPortfolio.Core.StockData;
+using MonoStockPortfolio.Entities;
+
+namespace MonoStockPortfolio.Tests.Services
+{
+    public class When_using_the_Yahoo_stock_data_service_to_get_quotes
+    {
+        static YahooStockDataProvider _svc;
+        static IList<StockQuote> _quotes;
+
+        Establish context = () =>
+            {
+                _svc = new YahooStockDataProvider();
+            };
+
+        Because of = () =>
+            {
+                _quotes = _svc.GetStockQuotes(new[] { "GOOG", "AMZN", "AAPL", "MSFT", "NOVL", "S", "VZ", "T" })
+                    .ToList();
+            };
+
+        It should_get_volumes_from_the_web = () =>
+            _quotes.ForEach(q => string.IsNullOrEmpty(q.Volume).ShouldBeFalse());
+        It should_get_last_trade_prices_from_the_web = () =>
+            _quotes.ForEach(q => q.LastTradePrice.ShouldNotEqual(0.0M));
+        It should_get_price_change_from_the_web = () =>
+            _quotes.ForEach(q => q.Change.ShouldNotEqual(0.0M));
+    }
+
+    public class When_using_the_Yahoo_stock_data_service_to_validate_tickers
+    {
+        static YahooStockDataProvider _svc;
+        static bool _goodTicker;
+        static bool _badTicker;
+
+        Establish context = () =>
+            {
+                _svc = new YahooStockDataProvider();
+            };
+
+        Because of = () =>
+            {
+                _goodTicker = _svc.IsValidTicker("GOOG");
+                _badTicker = _svc.IsValidTicker("GOOGAMOOGA");
+            };
+
+        It should_validate_the_good_ticker = () =>
+            _goodTicker.ShouldBeTrue();
+        It shouldnt_validate_the_bad_ticker = () =>
+            _badTicker.ShouldBeFalse();
+    }
+}
\ No newline at end of file
diff --git a/MonoStockPortfolio.Tests/YahooStockDataProviderTests.cs b/MonoStockPortfolio.Tests/YahooStockDataProviderTests.cs
deleted file mode 100644
index 69eb406..0000000
--- a/MonoStockPortfolio.Tests/YahooStockDataProviderTests.cs
+++ /dev/null
@@ -1,109 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using MonoStockPortfolio.Core.PortfolioRepositories;
-using MonoStockPortfolio.Core.Services;
-using MonoStockPortfolio.Core.StockData;
-using MonoStockPortfolio.Entities;
-using Xunit;
-
-namespace MonoStockPortfolio.Tests
-{
-    public class YahooStockDataProviderTests
-    {
-        [Fact]
-        public void Can_get_volume_from_web()
-        {
-            var svc = new YahooStockDataProvider();
-            var quotes = svc.GetStockQuotes(new[] {"GOOG", "AMZN", "AAPL", "MSFT", "NOVL", "S", "VZ", "T"});
-            foreach (var stockQuote in quotes)
-            {
-                Assert.True(!string.IsNullOrEmpty(stockQuote.Volume));
-            }
-            Assert.True(quotes.Any());
-        }
-
-        [Fact]
-        public void Can_get_volume_from_service()
-        {
-            var svc = new PortfolioService(BuildStubPortfolioRepo(), new YahooStockDataProvider());
-            var items = svc.GetDetailedItems(1, new List<StockDataItem> {StockDataItem.Ticker, StockDataItem.Volume});
-            foreach (var positionResultsViewModel in items)
-            {
-                Assert.True(positionResultsViewModel.Items[StockDataItem.Volume] != null);
-            }
-            Assert.True(items.Any());
-        }
-
-        [Fact]
-        public void Can_tell_if_a_ticker_is_valid()
-        {
-            var svc = new YahooStockDataProvider();
-            Assert.True(svc.IsValidTicker("GOOG"));
-        }
-
-        [Fact]
-        public void Can_tell_if_a_ticker_is_invalid()
-        {
-            var svc = new YahooStockDataProvider();
-            Assert.False(svc.IsValidTicker("HARBLHARBLHARBL"));
-        }
-
-        private IPortfolioRepository BuildStubPortfolioRepo()
-        {
-            return new StubPortfolioRepo();
-        }
-
-        public class StubPortfolioRepo : IPortfolioRepository
-        {
-            public IList<Position> GetAllPositions(long portfolioId)
-            {
-                return new List<Position>
-                           {
-                               new Position(1)
-                                   {ContainingPortfolioID = 1, PricePerShare = 5, Shares = 100, Ticker = "GOOG"}
-                           };
-            }
-
-            public IList<Portfolio> GetAllPortfolios()
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SavePortfolio(Portfolio portfolio)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void DeletePortfolioById(int portfolioId)
-            {
-                throw new NotImplementedException();
-            }
-
-            public Portfolio GetPortfolioById(long portfolioId)
-            {
-                throw new NotImplementedException();
-            }
-
-            public Portfolio GetPortfolioByName(string portfolioName)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void SavePosition(Position position)
-            {
-                throw new NotImplementedException();
-            }
-
-            public void DeletePositionById(long positionId)
-            {
-                throw new NotImplementedException();
-            }
-
-            public Position GetPositionById(long positionId)
-            {
-                throw new NotImplementedException();
-            }
-        }
-    }
-}
\ No newline at end of file
diff --git a/MonoStockPortfolio.sln b/MonoStockPortfolio.sln
index e312ac3..2804436 100644
--- a/MonoStockPortfolio.sln
+++ b/MonoStockPortfolio.sln
@@ -6,6 +6,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "libs", "libs", "{643BA3D4-E3D6-49B7-B347-2B935FD5B9FC}"
 	ProjectSection(SolutionItems) = preProject
 		libs\PostSharp.SL.dll = libs\PostSharp.SL.dll
+		libs\Telerik.JustMock.Silverlight.dll = libs\Telerik.JustMock.Silverlight.dll
 	EndProjectSection
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MonoStockPortfolio.Core", "MonoStockPortfolio.Core\MonoStockPortfolio.Core.csproj", "{251E7BB4-CFE2-4DE4-9E2A-AAE1AF41C8CB}"
diff --git a/MonoStockPortfolio/Resources/Resource.Designer.cs b/MonoStockPortfolio/Resources/Resource.Designer.cs
index 35980d9..86b6bc8 100644
--- a/MonoStockPortfolio/Resources/Resource.Designer.cs
+++ b/MonoStockPortfolio/Resources/Resource.Designer.cs
@@ -1,7 +1,7 @@
 //------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by a tool.
-//     Runtime Version:2.0.50727.4952
+//     Runtime Version:2.0.50727.5420
 //
 //     Changes to this file may cause incorrect behavior and will be lost if
 //     the code is regenerated.