final Throwable[] causes = mcae.getCauses();
                if (causes.length > 0) {
                    t = causes[causes.length - 1];
                }
            }

            String errorName;
            final Throwable cause = t.getCause();
            if (cause != null) {
                errorName = cause.getClass().getCanonicalName();

        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("Top level", topException.getMessage());
        assertEquals(middleCause, topException.getCause());
        assertEquals(rootCause, topException.getCause().getCause());
    }

    public void test_serialVersionUID() {
        // Test that serialVersionUID is properly defined

        assertEquals("Top level error", exception.getMessage());
        assertEquals(intermediateCause, exception.getCause());
        assertEquals("Intermediate cause", exception.getCause().getMessage());
        assertEquals(rootCause, exception.getCause().getCause());
        assertEquals("Root cause", exception.getCause().getCause().getMessage());
    }

    public void test_withLongMessage() {
        // Test with a very long message

        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);

        } catch (RuntimeException e) {
            assertEquals("Wrapper exception", e.getMessage());
            assertNotNull(e.getCause());
            assertTrue(e.getCause() instanceof FessUserNotFoundException);
            assertEquals("User is not found: testuser", e.getCause().getMessage());
        }
    }

    public void test_multipleInstances() {
        // Test that multiple instances are independent

        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());
    }

    public void test_throwAndCatch() {

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

    public void test_constructor_withSpecialCharactersInMessage() {
        // Test constructor with special characters in message

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

    public void test_constructor_withSpecialCharactersInUrl() {

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

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