@Test
  public void convertDatetimeStrToLongTest3() {
    zoneOffset = ZoneOffset.UTC;
    zoneId = ZoneId.of("Etc/UTC");
    delta = 8 * 3600000;
    // 2019-01-02T00:00:00.000+08:00
    long timestamp1 = 1546358400000L;
    testConvertDateStrToLong(zoneOffset, zoneId, timestamp1 + delta);
  }
Test convertDatetimeStrToLong() method with different time precision.
iotdb-core/datanode/src/test/java/org/apache/iotdb/db/utils/DateTimeUtilsTest.java