assertTrue(e2.getMessage().contains("Already closed"));
    }

    @Test
    @DisplayName("ensureOpen throws after close() is called")
    void testEnsureOpenAfterClose() throws CIFSException {
        target.close();
        CIFSException ex = assertThrows(SmbException.class, () -> target.ensureOpen());
        assertTrue(ex.getMessage().contains("Pipe handle already closed"));