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

NUnit.Framework.Interfaces.IApplyToTestSuite

public interface IApplyToTestSuite
The IApplyToTestSuite interface is implemented by self-applying attributes that modify the state of a test suite in some way.
namespace NUnit.Framework.Interfaces { public interface IApplyToTestSuite { void ApplyToTestSuite(TestSuite testSuite); } }