Fix DateTime looses significant digits in DynamicData (microsoft#875) (…

…microsoft#907)

src/Adapter/MSTest.CoreAdapter/Helpers/DataSerializationHelper.cs

@@ -17,7 +17,8 @@ internal static class DataSerializationHelper
         private static readonly DataContractJsonSerializerSettings SerializerSettings = new DataContractJsonSerializerSettings()
         {
             UseSimpleDictionaryFormat = true,
-            EmitTypeInformation = System.Runtime.Serialization.EmitTypeInformation.Always
+            EmitTypeInformation = System.Runtime.Serialization.EmitTypeInformation.Always,
+            DateTimeFormat = new System.Runtime.Serialization.DateTimeFormat("O", System.Globalization.CultureInfo.InvariantCulture)
         };
 
         /// <summary>

test/UnitTests/MSTest.CoreAdapter.Unit.Tests/Helpers/DataSerializationHelperTests.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.VisualStudio.TestPlatform.MSTestAdapter.UnitTests
+{
+    extern alias FrameworkV1;
+    extern alias FrameworkV2;
+
+    using System;
+    using FluentAssertions;
+    using Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.Helpers;
+
+    using TestableImplementations;
+    using Assert = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.Assert;
+    using CollectionAssert = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.CollectionAssert;
+    using TestClass = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.TestClassAttribute;
+    using TestCleanup = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.TestCleanupAttribute;
+    using TestInitialize = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.TestInitializeAttribute;
+    using TestMethod = FrameworkV1::Microsoft.VisualStudio.TestTools.UnitTesting.TestMethodAttribute;
+    using UTF = FrameworkV2::Microsoft.VisualStudio.TestTools.UnitTesting;
+
+    [TestClass]
+    public class DataSerializationHelperTests
+    {
+        [TestMethod]
+        public void DataSerializerShouldRoundTripDateTimeOffset()
+        {
+            var source = new DateTimeOffset(628381323438126060, TimeSpan.FromHours(-8));
+
+            var actual = DataSerializationHelper.Deserialize(
+                DataSerializationHelper.Serialize(new object[] { source }));
+
+            actual.Should().HaveCount(1);
+            actual[0].Should().BeOfType<DateTimeOffset>();
+            actual[0].As<DateTimeOffset>().Should().Be(source);
+        }
+
+        [TestMethod]
+        public void DataSerializerShouldRoundTripDateTime()
+        {
+            var source = new DateTime(628381323438126060);
+
+            var actual = DataSerializationHelper.Deserialize(
+                DataSerializationHelper.Serialize(new object[] { source }));
+
+            actual.Should().HaveCount(1);
+            actual[0].Should().BeOfType<DateTime>();
+            actual[0].As<DateTime>().Should().Be(source);
+            actual[0].As<DateTime>().Kind.Should().Be(source.Kind);
+        }
+
+        [TestMethod]
+        public void DataSerializerShouldRoundTripDateTimeOfKindLocal()
+        {
+            var source = new DateTime(628381323438126060, DateTimeKind.Local);
+
+            var actual = DataSerializationHelper.Deserialize(
+                DataSerializationHelper.Serialize(new object[] { source }));
+
+            actual.Should().HaveCount(1);
+            actual[0].Should().BeOfType<DateTime>();
+            actual[0].As<DateTime>().Should().Be(source);
+            actual[0].As<DateTime>().Kind.Should().Be(source.Kind);
+        }
+
+        [TestMethod]
+        public void DataSerializerShouldRoundTripDateTimeOfKindUtc()
+        {
+            var source = new DateTime(628381323438126060, DateTimeKind.Utc);
+
+            var actual = DataSerializationHelper.Deserialize(
+                DataSerializationHelper.Serialize(new object[] { source }));
+
+            actual.Should().HaveCount(1);
+            actual[0].Should().BeOfType<DateTime>();
+            actual[0].As<DateTime>().Should().Be(source);
+            actual[0].As<DateTime>().Kind.Should().Be(source.Kind);
+        }
+    }
+}

test/UnitTests/MSTest.CoreAdapter.Unit.Tests/MSTest.CoreAdapter.Unit.Tests.csproj

@@ -38,7 +38,7 @@
     <Reference Include="System.Configuration" />
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
-    
+
     <Reference Include="Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
       <Aliases>FrameworkV1</Aliases>
       <Private>True</Private>
@@ -83,7 +83,7 @@
     <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Version="$(MicrosoftNETTestSdkVersion)" />
     <PackageReference Include="Moq" Version="$(MoqVersion)" />
     <PackageReference Include="FluentAssertions" Version="$(FluentAssertionsVersion)" />
-
+    
     <PackageReference Include="StyleCop.Analyzers" Version="$(StyleCopAnalyzersVersion)" PrivateAssets="all">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
@@ -116,6 +116,7 @@
     <Compile Include="Extensions\TestContextExtensionsTests.cs" />
     <Compile Include="Extensions\TestResultExtensionsTests.cs" />
     <Compile Include="Extensions\UnitTestOutcomeExtensionsTests.cs" />
+    <Compile Include="Helpers\DataSerializationHelperTests.cs" />
     <Compile Include="Helpers\DictionaryHelperTests.cs" />
     <Compile Include="Helpers\ReflectHelperTests.cs" />
     <Compile Include="Helpers\RunSettingsUtilitiesTests.cs" />