assertTrue(json.contains("\"must\""));
        assertTrue(json.contains("\"heartbeat\""));
        assertTrue(json.contains("\"gte\""));
    }

    @Test
    public void test_parseJson_nestedStructure() {
        final String json = "{\"hits\":{\"hits\":[{\"_source\":{\"instanceId\":\"test\",\"hostname\":\"host1\"}}]}}";
        final Map<String, Object> result = coordinatorHelper.parseJson(json);