Update test deps

Ix.NET/Source/Directory.build.props

@@ -20,14 +20,9 @@
     <LangVersion>8.0</LangVersion>
   </PropertyGroup>
 
-  <!-- Hack needed to make code coverage work. See https://github.com/Microsoft/vstest/issues/1748. -->
-  <PropertyGroup Condition="'$(Configuration)' == 'Debug'">
-    <DebugType>full</DebugType>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta2-18618-05" PrivateAssets="All"/>
-    <PackageReference Include="Nerdbank.GitVersioning" Version="2.3.38" PrivateAssets="all" />
+    <PackageReference Include="Nerdbank.GitVersioning" Version="2.3.105" PrivateAssets="all" />
   </ItemGroup>
 
   <Target Name="AddCommitHashToAssemblyAttributes" BeforeTargets="GetAssemblyAttributes">

Ix.NET/Source/Directory.build.targets

@@ -10,7 +10,7 @@
   <PropertyGroup Condition="'$(TargetFramework)' == 'net45'">
     <DefineConstants>$(DefineConstants);NO_ARRAY_EMPTY;NO_TASK_FROMEXCEPTION</DefineConstants>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0' or '$(TargetFramework)' == 'netstandard2.1'">
     <!--
     NB: USE_ASYNC_ITERATOR relies on members in the framework only present in .NET Core 3.0 Preview 2 at the moment:
           error CS0518: Predefined type 'System.Runtime.CompilerServices.AsyncIteratorMethodBuilder' is not defined or imported

Ix.NET/Source/System.Interactive.Tests/System.Interactive.Tests.csproj

@@ -17,11 +17,11 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.0.0-preview-20190203-03" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <PackageReference Include="FluentAssertions" Version="4.19.2 " />
     
-    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
   </ItemGroup>
 
 </Project>

Ix.NET/Source/System.Interactive.Tests/System/Linq/Operators/Buffer.cs

@@ -52,7 +52,7 @@ namespace Tests
             var rng = Enumerable.Empty<int>();
 
             var res = rng.Buffer(5).ToList();
-            Assert.Equal(0, res.Count);
+            Assert.Empty(res);
         }
 
         [Fact]

Ix.NET/Source/System.Linq.Async.Queryable.Tests/System.Linq.Async.Queryable.Tests.csproj

@@ -18,11 +18,11 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.0.0-preview-20190203-03" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <PackageReference Include="FluentAssertions" Version="4.19.2 " />
 
-    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit" Version="2.4.01" />
   </ItemGroup>
 
   <ItemGroup>

Ix.NET/Source/System.Linq.Async.Queryable/System.Linq.Async.Queryable.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;net46;netstandard1.4;netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>net45;net46;netstandard1.4;netstandard2.0;netstandard2.1;netcoreapp3.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
@@ -23,8 +23,4 @@
     </None>
   </ItemGroup>
 
-  <ItemGroup>
-    <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" />
-  </ItemGroup>
-
 </Project>

Ix.NET/Source/System.Linq.Async.Tests/System.Linq.Async.Tests.csproj

@@ -36,11 +36,11 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.8.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.0.0-preview-20190203-03" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <PackageReference Include="FluentAssertions" Version="4.19.2 " />
 
-    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit" Version="2.4.1" />
   </ItemGroup>
 
   <ItemGroup>

Ix.NET/Source/System.Linq.Async/System.Linq.Async.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;net46;netstandard1.4;netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>net45;net46;netstandard1.4;netstandard2.0;netstandard2.1;netcoreapp3.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
@@ -18,7 +18,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.1" />
+    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.2" />
   </ItemGroup>
 
   <ItemGroup>
@@ -72,8 +72,4 @@
     </None>
   </ItemGroup>
 
-  <ItemGroup>
-    <Service Include="{508349b6-6b84-4df5-91f0-309beebad82d}" />
-  </ItemGroup>
-
 </Project>