// Arrange & Act
        SMBSignatureValidationException ex = new SMBSignatureValidationException();

        // Assert
        assertNull(ex.getMessage(), "Default ctor should not set a message");
        assertNull(ex.getCause(), "Default ctor should not set a cause");
        assertTrue(ex instanceof SmbException, "Should be an SmbException subtype");

        // Arrange & Act
        SMBProtocolDecodingException ex = new SMBProtocolDecodingException();

        // Assert state
        assertNull(ex.getMessage(), "Default constructor should have null message");
        assertNull(ex.getCause(), "Default constructor should have null cause");
        assertTrue(ex instanceof CIFSException, "Should be a CIFSException subtype");

        SmbEndOfFileException ex = new SmbEndOfFileException();

        // Assert
        assertEquals("Unexpectedly reached end of file", ex.getMessage(), "Default message must match");
        assertEquals(NtStatus.NT_STATUS_UNSUCCESSFUL, ex.getNtStatus(), "Default NT status should be UNSUCCESSFUL");
        assertNull(ex.getCause(), "Cause should be null by default");

    private final RuntimeException ex;

    private ThrowingIterator(RuntimeException ex) {
      this.ex = ex;
    }

    @Override
    public boolean hasNext() {
      // IteratorTester doesn't expect exceptions for hasNext().
      return true;
    }

    @Override
    public E next() {
      ex.fillInStackTrace();
      throw ex;
    }

    @Override

        // Using an uppercase short name (no dot) must throw an unsupported operation
        SmbUnsupportedOperationException ex =
                assertThrows(SmbUnsupportedOperationException.class, () -> auth.createContext(tc, null, "SERVER", new byte[0], false));
        assertTrue(ex.getMessage().contains("Cannot use netbios/short names"));
    }

    @Test

        // Act & Assert: both UnknownHostException and IOException should become CIFSException (SmbException)
        CIFSException ex = assertThrows(CIFSException.class, () -> trace.connectWrapException(loc));
        assertTrue(ex.getMessage() != null && ex.getMessage().contains("Failed to connect to server"));
        assertSame(thrown, ex.getCause());
    }

    @Test
    @DisplayName("connectWrapException: rethrows SmbException unchanged")

            } finally {
                CloseableUtil.close(ois);
            }
        } catch (final IOException ex) {
            throw new IORuntimeException(ex);
        } catch (final ClassNotFoundException ex) {
            throw new ClassNotFoundRuntimeException(ex);
        }
    }

        // Act + Assert: exception is propagated with message
        CIFSException ex = assertThrows(CIFSException.class, () -> handle.ensureDFSResolved());
        assertEquals("DFS resolution failed", ex.getMessage());
        verify(handle, times(1)).ensureDFSResolved();
    }

    @ParameterizedTest

        assertEquals(boolean.class, m2.getReturnType());
        assertEquals(1, m2.getParameterCount());
        Class<?>[] ex = m2.getExceptionTypes();
        assertEquals(1, ex.length);
        assertEquals(CIFSException.class, ex[0]);

        // handleDFSReferral(DfsReferralData, String): String, no checked exceptions

                        try {
                            handlerClass = Class.forName(className);
                        } catch (final Exception ex) {
                            log.debug("Failed to load handler class " + className, ex);
                        }
                        if (handlerClass == null) {
                            handlerClass = ClassLoader.getSystemClassLoader().loadClass(className);