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();

   *
   * <p>Prefer this method instead of manually casting an exception's cause. For example, {@code
   * (IOException) e.getCause()} throws a {@link ClassCastException} that discards the original
   * exception {@code e} if the cause is not an {@link IOException}, but {@code
   * Throwables.getCauseAs(e, IOException.class)} keeps {@code e} as the {@link
   * ClassCastException}'s cause.
   *

        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("dbConnection", topException.getComponentName());
        assertEquals(middleCause, topException.getCause());
        assertEquals(rootCause, topException.getCause().getCause());
    }

    public void test_throwAndCatch() {
        // Test throwing and catching the exception
        String componentName = "cacheManager";
        try {

        // Verify cause chain is preserved
        assertEquals(middleCause, exception.getCause());
        assertEquals(rootCause, exception.getCause().getCause());
    }

    public void test_emptyMessage() {
        // Setup
        final String message = "";

        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

        final SsoMessageException exception = new SsoMessageException(messageCode, message, middleCause);

        // Verify cause chain
        assertEquals(middleCause, exception.getCause());
        assertEquals(rootCause, exception.getCause().getCause());
    }

    public void test_emptyMessage() {
        // Setup
        final String message = "";