final Map<String, Object> result = coordinatorHelper.parseJson(null);
        assertNotNull(result);
        assertTrue(result.isEmpty());
    }

    @Test
    public void test_toJson_and_parseJson_roundtrip() {
        final Map<String, Object> original = new LinkedHashMap<>();
        original.put("type", "operation");
        original.put("name", "reindex");
        original.put("status", "running");