}

    @Test
    public void test_nullSafeLogout() {
        SpnegoAuthenticator authenticator = new SpnegoAuthenticator();

        // SPNEGO logout should return null (relies on Kerberos infrastructure)
        String logoutUrl = authenticator.logout(null);
        assertNull(logoutUrl);
    }

    @Test
    public void test_nullSafeGetResponse() {

│   ├── service/               # Business logic services
│   ├── pager/                 # Pagination handlers
│   └── job/                   # Background jobs
├── api/                       # REST API infrastructure
├── opensearch/                # DBFlute integration for OpenSearch
│   ├── config/                # Config index (crawl configs, schedules)
│   ├── log/                   # Log index (search logs, click logs)

- **Search Features**: Facets, suggestions, security filtering, ranking rules
- **Integration Points**: Applications consuming search APIs
- **User Permissions**: Access control and label configurations

### 2. Infrastructure Requirements

Ensure your Fess environment meets these requirements:

- **Java**: JDK 17 or later
- **Memory**: Minimum 4GB RAM (8GB+ recommended for production)
- **Storage**: At least 2x your current index size

        return null;
    }

    /**
     * Performs logout for the specified user.
     *
     * SPNEGO authentication relies on the underlying Kerberos infrastructure
     * for session management, so no specific logout URL is provided.
     *
     * @param user The user to logout
     * @return Always returns null as SPNEGO doesn't provide a logout URL
     */
    @Override

import com.fasterxml.jackson.databind.ObjectMapper;

import jakarta.servlet.http.HttpSession;

/**
 * Abstract base class for LLM client implementations.
 *
 * Provides shared infrastructure (HTTP client, availability checking) and
 * default implementations of RAG workflow methods with injectable prompt templates.
 * Subclasses implement provider-specific chat/streamChat and checkAvailabilityNow.
 */