*
     * @param operationName the operation name to look up.
     * @return an {@link Optional} containing the operation info, or empty if not found.
     */
    public Optional<OperationInfo> getOperationInfo(final String operationName) {
        try (CurlResponse response = ComponentUtil.getCurlHelper() //
                .get("/" + getIndexName() + "/_doc/" + operationName) //
                .execute()) {

    }

    // ===================================================================================
    //                                                             getOperationInfo
    //                                                             ==================

    @Test
    public void test_getOperationInfo_found() {
        setupMockFessConfig();

        if (!coordinator.tryStartOperation("reload_doc_index")) {
            saveError(messages -> messages.addErrorsOperationAlreadyRunning(GLOBAL,
                    coordinator.getOperationInfo("reload_doc_index").map(o -> o.hostname).orElse("unknown")));
            return redirect(getClass());
        }
        try {
            searchEngineClient.flushConfigFiles(() -> {