public void Should_be_able_fluently_to_configure_the_policy_key_via_interface() { ISyncPolicy <int> policyAsInterface = Policy.HandleResult <int>(0).Retry(); var policyAsInterfaceAfterWithPolicyKey = policyAsInterface.WithPolicyKey(Guid.NewGuid().ToString()); policyAsInterfaceAfterWithPolicyKey.Should().BeAssignableTo <ISyncPolicy <int> >(); }