@Nested
    @DisplayName("Interface Edge Case Handling")
    class InterfaceEdgeCaseTests {

        @Test
        @DisplayName("Should handle null SID from interface methods")
        void shouldHandleNullSID() {
            ACE ace = mock(ACE.class);
            when(ace.getSID()).thenReturn(null);

            SID result = ace.getSID();
            assertNull(result, "getSID() should return null when configured");