<PackageReference Include="NUnit" Version="4.3.2" />

NUnit.Framework.Guard

static class Guard
Class used to guard against unexpected argument values or operations by throwing an appropriate exception.
namespace NUnit.Framework { internal static class Guard { public static void ArgumentNotNull(object value, string name); public static void ArgumentNotNullOrEmpty(string value, string name); public static void ArgumentInRange(bool condition, string message, string paramName); public static void ArgumentValid(bool condition, string message, string paramName); public static void OperationValid(bool condition, string message); public static void ArgumentNotAsyncVoid(Delegate delegate, string paramName); public static void ArgumentNotAsyncVoid(MethodInfo method, string paramName); } }