ArgumentCaptor<Integer> codeCap = ArgumentCaptor.forClass(Integer.class);
        ArgumentCaptor<String> msgCap = ArgumentCaptor.forClass(String.class);
        verify(handler, atLeastOnce()).handle(codeCap.capture(), msgCap.capture());

        // Assert at least one captured pair is a known mapping (happy path spot check)
        assertTrue(codeCap.getAllValues().contains(WinError.ERROR_ACCESS_DENIED));