// 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());

        assertNull(exception.getCause());
    }

    @Test
    public void test_constructor_withMessageAndCause() {
        // Test constructor with message and cause
        String message = "Test error message";
        Throwable cause = new RuntimeException("Underlying cause");
        SearchEngineClientException exception = new SearchEngineClientException(message, cause);

        assertNotNull(exception);

        assertEquals(message, exception.getMessage());
        assertEquals(outerCause, exception.getCause());
        assertEquals(middleCause, exception.getCause().getCause());
        assertEquals(innerCause, exception.getCause().getCause().getCause());
        assertFalse(exception.aborted());
    }

    @Test
    public void test_constructor_withSpecialCharactersInUrl() {

        assertEquals(middleCause, exception.getCause());
        assertEquals(rootCause, exception.getCause().getCause());
    }

    @Test
    public void test_exceptionSerialization() {
        // Test that the exception is serializable
        String message = "Serialization test";
        Exception cause = new Exception("Test cause");

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

    @Test
    public void test_withLongMessage() {
        // Test with a very long message
        StringBuilder longMessage = new StringBuilder();
        for (int i = 0; i < 1000; i++) {
            longMessage.append("Error message part ").append(i).append(" ");

        assertEquals("LDAP operation failed", exception.getMessage());
        assertEquals(middleCause, exception.getCause());
        assertEquals("LDAP configuration error", exception.getCause().getMessage());
        assertEquals(innerCause, exception.getCause().getCause());
        assertEquals("Invalid LDAP parameter", exception.getCause().getCause().getMessage());
    }

    @Test
    public void test_throwAndCatch() {

        assertEquals(cause, exception.getCause());
    }

    @Test
    public void test_constructor_withCause() {
        // Test constructor with cause only
        Throwable cause = new IllegalArgumentException("Cause exception");
        FessSystemException exception = new FessSystemException(cause);

        assertEquals(cause, exception.getCause());
        // When constructed with cause only, message contains the cause's toString()

        assertEquals(componentName + " is not available.", exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertEquals(componentName, exception.getComponentName());
    }

    @Test
    public void test_constructor_withCause() {
        // Test constructor with cause only

        assertEquals(level1, topLevel.getCause());
        assertEquals("Level 1: Authentication service error", topLevel.getCause().getMessage());
        assertEquals(level2, topLevel.getCause().getCause());
        assertEquals("Level 2: User lookup failed", topLevel.getCause().getCause().getMessage());
        assertEquals(level3, topLevel.getCause().getCause().getCause());

        assertEquals("Theme operation failed", exception.getMessage());
        assertNotNull(exception.getCause());
        assertEquals(middleCause, exception.getCause());
        assertEquals("Processing failed", exception.getCause().getMessage());

        // Check nested cause
        Throwable nestedCause = exception.getCause().getCause();
        assertNotNull(nestedCause);
        assertEquals(innerCause, nestedCause);