"config_id", "W01", //
                "url", "http://test.com/001"//
        )));
        docList.add(new HashMap<>(Map.of(//
                "_id", "002", //
                "thumbnail", "http://test.com/002", //
                "url", "http://test.com/002"//
        )));
        indexingHelper.sendDocuments(client, docList);
        assertEquals(0, docList.size());
        assertEquals(2, sentDocList.size());

    }

    @Test
    public void test_generate_withNullOutputFile() {
        // Test generation with null output file
        String thumbnailId = "test-thumbnail-002";
        assertFalse(thumbnailGenerator.generate(thumbnailId, null));
    }

    @Test
    public void test_generate_withInvalidOutputPath() throws IOException {
        // Test generation with non-writable output file