<PackageReference Include="NUnit" Version="3.9.0" />

ConstraintUtils

static class ConstraintUtils
Provides methods to support consistent checking for constaints methods.
using System; namespace NUnit.Framework.Internal { internal static class ConstraintUtils { public static T RequireActual<T>(object actual, string paramName, bool allowNull = false) { if (actual is T) return (T)actual; if (allowNull && actual == null && default(T) == null) return default(T); string arg = (actual == null) ? "null" : actual.GetType().get_Name(); throw new ArgumentException($"""{typeof(T).get_Name()}""{arg}", paramName); } } }