*/
    public static final String HTTP_ADDRESS = "crawler.opensearch.http_address";

    /**
     * Target indices for OpenSearch.
     */
    public static final String TARGET_INDICES = "crawler.opensearch.target_indices";

    /**
     * Logger instance.
     */
    private static final Logger logger = LogManager.getLogger(FesenClient.class);

    /**
     * The OpenSearch client.
     */

            // This test verifies the null check logic indirectly
            final String[] indices = fesenClient.targetIndices != null ? fesenClient.targetIndices : new String[0];
            assertNotNull(indices);
            assertEquals(0, indices.length);
        } catch (Exception e) {
            fail("Should handle null targetIndices: " + e.getMessage());
        }
    }

    /**