assertTrue(ex.getMessage().contains("Pipe handle already closed"));
    }

    @Test
    @DisplayName("close() calls handle.close when open and handle.release otherwise; releases tree")
    void testCloseBehavior() throws CIFSException {
        when(pipe.ensureTreeConnected()).thenReturn(tree);
        when(tree.acquire()).thenReturn(tree);
        when(tree.isSMB2()).thenReturn(true);