<PackageReference Include="NUnit" Version="4.5.1" />

NUnit.Framework.Internal.NetPlatformHelper

public static class NetPlatformHelper
Class is used by the NetPlatformAttribute class to determine whether a platform is supported.
public static bool IsPlatformSupported(string[] platforms)

Test to determine if one of a collection of platforms is being used currently.

public static bool IsPlatformSupported(string platform)

Test to determine if a particular platform or comma-delimited set of platforms is in use.