Add tests for TypeForwardedFromAttribute (dotnet#27599)

Fixes #27554

Author: jkotas

src/System.Runtime/tests/System.Runtime.Tests.csproj

@@ -165,6 +165,7 @@
     <Compile Include="System\Reflection\TypeTests.GetMember.cs" />
     <Compile Include="System\Runtime\MemoryFailPointTests.cs" />
     <Compile Include="System\Runtime\NgenServicingAttributesTests.cs" />
+    <Compile Include="System\Runtime\CompilerServices\AttributesTests.cs" />
     <Compile Include="System\Runtime\CompilerServices\ConditionalWeakTableTests.cs" />
     <Compile Include="System\Runtime\CompilerServices\StrongBoxTests.cs" />
     <Compile Include="System\Runtime\CompilerServices\RuntimeHelpersTests.cs" />

src/System.Runtime/tests/System/Runtime/CompilerServices/AttributesTests.cs

@@ -0,0 +1,22 @@
+// 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.
+
+using Xunit;
+
+namespace System.Runtime.CompilerServices.Tests
+{
+    public static class AttributesTests
+    {
+        [Fact]
+        public static void TypeForwardedToAttributeTests()
+        {
+            string assemblyFullName = "MyAssembly";
+            var attr = new TypeForwardedFromAttribute(assemblyFullName);
+            Assert.Equal(assemblyFullName, attr.AssemblyFullName);
+
+            AssertExtensions.Throws<ArgumentNullException>("assemblyFullName", () => new TypeForwardedFromAttribute(null));
+            AssertExtensions.Throws<ArgumentNullException>("assemblyFullName", () => new TypeForwardedFromAttribute(""));
+        }
+    }
+}