Throwable cause1 = exception.getCause();
        assertNotNull(cause1);
        assertTrue(cause1 instanceof IOException);
        assertEquals("Level 1 error", cause1.getMessage());

        Throwable cause2 = cause1.getCause();
        assertNotNull(cause2);
        assertTrue(cause2 instanceof IllegalStateException);
        assertEquals("Level 2 error", cause2.getMessage());

        // Test constructor with null message but valid cause
        Exception cause = new IllegalArgumentException("Invalid argument");
        DictionaryException exception = new DictionaryException(null, cause);

        assertNotNull(exception);
        assertNull(exception.getMessage());
        assertNotNull(exception.getCause());
        assertEquals(cause, exception.getCause());
    }

        });

        // Test throwing and catching with cause
        RuntimeException cause = new RuntimeException("Cause");
        TransportException thrown = assertThrows(TransportException.class, () -> {
            throw new TransportException(cause);
        });
        assertEquals(cause, thrown.getCause());

        // Test throwing and catching with message and cause

        // Test constructor with message and cause
        String message = "Storage operation failed";
        Exception cause = new RuntimeException("Underlying error");
        StorageException exception = new StorageException(message, cause);

        assertNotNull(exception);
        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
    }

        // Arrange - use a real cause so message is derived from cause.toString()
        Throwable cause = new IllegalStateException("proto mismatch");
        String expectedMessage = cause.toString();

        // Act
        SMBProtocolDowngradeException ex = new SMBProtocolDowngradeException(cause);

        // Assert - cause preserved, message derived from cause
        assertSame(cause, ex.getCause());

        // Expect the message to be set correctly and cause to be null
        assertEquals(errorMessage, e.getMessage());
        assertNull(e.getCause());
    }

    /**
     * Test the constructor with a cause.
     */
    @Test
    void testCauseConstructor() {
        Throwable cause = new RuntimeException("Root cause");
        PACDecodingException e = new PACDecodingException(cause);

    void testWithCause() {
        // Given
        IllegalArgumentException cause = new IllegalArgumentException("bad arg");

        // When
        SpnegoException ex = new SpnegoException(cause);

        // Then
        assertNotNull(ex);
        assertEquals(cause, ex.getCause());
        // IOException(Throwable) sets message to cause.toString()

        // Test constructor with message and cause
        String message = "Test scheduled job error with cause";
        Throwable cause = new RuntimeException("Root cause exception");
        ScheduledJobException exception = new ScheduledJobException(message, cause);

        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertEquals("Root cause exception", exception.getCause().getMessage());

    void testToStringWithRootCause() {
        RuntimeException cause = new RuntimeException("boom");
        SmbException ex = new SmbException(0, cause);
        assertTrue(ex.toString().contains("RuntimeException"), "String representation must include the root cause stack trace");
    }

    /**
     * Verify that {@link #toString()} with no root cause equals the default

    /**
     * Constructs a new FessSystemException with the specified detail message and cause.
     *
     * @param message the detail message describing the exception
     * @param cause the cause of this exception
     */
    public FessSystemException(final String message, final Throwable cause) {
        super(message, cause);
    }

    /**
     * Constructs a new FessSystemException with the specified detail message.