Added NullableExtensions tests

Author: Sergio0694

UnitTests/UnitTests.HighPerformance.Shared/Extensions/Test_NullableExtensions.cs

@@ -0,0 +1,42 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#if NET5_0
+
+using System.Numerics;
+using Microsoft.Toolkit.HighPerformance.Extensions;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace UnitTests.HighPerformance.Extensions
+{
+    [TestClass]
+    public class Test_NullableExtensions
+    {
+        [TestCategory("NullableExtensions")]
+        [TestMethod]
+        public void Test_NullableExtensions_DangerousGetReference()
+        {
+            static void Test<T>(T before, T after)
+                where T : struct
+            {
+                T? nullable = before;
+                ref T reference = ref nullable.DangerousGetValueOrDefaultReference();
+
+                Assert.AreEqual(nullable.Value, before);
+
+                reference = after;
+
+                Assert.AreEqual(nullable.Value, after);
+            }
+
+            Test(0, 42);
+            Test(1.3f, 3.14f);
+            Test(0.555, 8.49);
+            Test(Vector4.Zero, new Vector4(1, 5.55f, 2, 3.14f));
+            Test(Matrix4x4.Identity, Matrix4x4.CreateOrthographic(35, 88.34f, 9.99f, 24.6f));
+        }
+    }
+}
+
+#endif

UnitTests/UnitTests.HighPerformance.Shared/UnitTests.HighPerformance.Shared.projitems

@@ -28,6 +28,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_BoolExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_HashCodeExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_IBufferWriterExtensions.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_NullableExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_StreamExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_SpanExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\Test_ReadOnlySpanExtensions.Count.cs" />