*/
public class LlmException extends FessSystemException {

    private static final long serialVersionUID = 1L;

    /** Error code for rate limit (HTTP 429). */
    public static final String ERROR_RATE_LIMIT = "rate_limit";

    /** Error code for authentication failure (HTTP 401/403). */
    public static final String ERROR_AUTH = "auth_error";

    /** Error code for service unavailable (HTTP 502/503). */

        assertEquals(LlmException.ERROR_AUTH, exception.getErrorCode());
        assertSame(cause, exception.getCause());
    }

    @Test
    public void test_errorCodeConstants() {
        assertEquals("rate_limit", LlmException.ERROR_RATE_LIMIT);
        assertEquals("auth_error", LlmException.ERROR_AUTH);
        assertEquals("service_unavailable", LlmException.ERROR_SERVICE_UNAVAILABLE);