<PackageReference Include="NUnit" Version="4.6.1" />

NUnit.Framework.Constraints.SameAsConstraint<T>

public class SameAsConstraint<T> : SameAsConstraint
SameAsConstraint tests whether an object is identical to the object passed to its constructor
public SameAsConstraint(T expected)

SameAsConstraint tests whether an object is identical to the object passed to its constructor