static String getModel(String fileName) {
        return FileNameUtils.getSuffix(fileName).replace(FINAL_SUFFIX, "");
    }
@Test
    void testGetModel() {
        String fileName = String.format("%1$sthis%1$sis%1$svalid%1$sfile.model_json", File.separator);
        String expected = "model";
        IndexFile indexFile = new IndexFile(fileName);
        assertThat(indexFile.getModel()).isEqualTo(expected);
    }