<PackageReference Include="NUnit" Version="4.3.1" />

IConstraint

public interface IConstraint : IResolveConstraint
Interface for all constraints
using System.Runtime.CompilerServices; namespace NUnit.Framework.Constraints { [System.Runtime.CompilerServices.NullableContext(1)] public interface IConstraint : IResolveConstraint { string DisplayName { get; } string Description { get; } [System.Runtime.CompilerServices.Nullable(new byte[] { 1, 2 })] object[] Arguments { [return: System.Runtime.CompilerServices.Nullable(new byte[] { 1, 2 })] get; } [System.Runtime.CompilerServices.Nullable(2)] ConstraintBuilder Builder { [System.Runtime.CompilerServices.NullableContext(2)] get; [System.Runtime.CompilerServices.NullableContext(2)] set; } ConstraintResult ApplyTo<[System.Runtime.CompilerServices.Nullable(2)] TActual>(TActual actual); ConstraintResult ApplyTo<[System.Runtime.CompilerServices.Nullable(2)] TActual>(ActualValueDelegate<TActual> del); ConstraintResult ApplyTo<[System.Runtime.CompilerServices.Nullable(2)] TActual>(ref TActual actual); } }