@SuppressWarnings("unchecked")
    public void test_indexFromEmptyDocuments() throws Exception {
        Map<String, Object>[] documents = new Map[0];
        SuggestIndexResponse response = suggester.indexer().indexFromDocument(documents);

        assertNotNull(response);
        assertEquals(0, response.getNumberOfInputDocs());
        assertFalse(response.hasError());
    }

    @Test

     * @param documents The documents to index.
     * @return The SuggestIndexResponse.
     */
    public SuggestIndexResponse indexFromDocument(final Map<String, Object>[] documents) {
        ensureOperations();
        return contentOps.indexFromDocument(createContext(), documents);
    }

    /**
     * Indexes documents from a DocumentReader asynchronously.

        documents[0].put(field, "これはテストです");

        documents[1] = new HashMap<>();
        documents[1].put(field, "検索エンジン");

        SuggestIndexResponse response = suggester.indexer().indexFromDocument(documents);

        assertNotNull(response);
        assertEquals(2, response.getNumberOfInputDocs());
        assertFalse(response.hasError());
    }

    @Test

        final int docPerReq = fessConfig.getSuggestUpdateDocPerRequestAsInteger();
        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        suggester.indexer().indexFromDocument(() -> {
            final ESSourceReader reader = new ESSourceReader(ComponentUtil.getSearchEngineClient(), suggester.settings(),
                    fessConfig.getIndexDocumentSearchIndex());