<PackageReference Include="NUnit" Version="4.2.2" />

NUnit.Framework.Constraints.ExactCountConstraint

ExactCountConstraint applies another constraint to each item in a collection, succeeding only if a specified number of items succeed.
namespace NUnit.Framework.Constraints { public class ExactCountConstraint : Constraint { public ExactCountConstraint(int expectedCount); public ExactCountConstraint(int expectedCount, IConstraint itemConstraint); } }