combine from test utilities

Author: twsouthwick

src/Shared/FxPolyfills/IsExternalInit.cs

@@ -0,0 +1,12 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#if NETFRAMEWORK
+
+namespace System.Runtime.CompilerServices;
+
+internal static class IsExternalInit
+{
+}
+
+#endif

src/Shared/FxPolyfills/OperatingSystem.cs

@@ -0,0 +1,18 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#if NETFRAMEWORK
+
+namespace System;
+
+internal static class FrameworkExtensions
+{
+    extension(OperatingSystem)
+    {
+        public static bool IsLinux() => false;
+        public static bool IsWindows() => true;
+        public static bool IsMacOS() => false;
+    }
+}
+
+#endif

tests/Aspire.TestUtilities/Aspire.TestUtilities.csproj

@@ -9,5 +9,10 @@
     <PackageReference Include="Microsoft.DotNet.XUnitV3Extensions" />
     <PackageReference Include="OpenTelemetry.Extensions.Hosting" />
   </ItemGroup>
+  
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
+    <PackageReference Include="Microsoft.Bcl.Memory" />
+  </ItemGroup>
 
+  <Import Project="../../src/Shared/FxPolyfills/FxPolyfills.targets" />
 </Project>