@Test
public void sendPhysicalTimeInThePast() {

  final long inThePast = 1489018784131L;
  final DefaultVersionService.Clock clock = () -> inThePast;
  DefaultVersionService v = new DefaultVersionService(clock);
  final DefaultVersionService.HybridLogicalTimestamp send = v.nextVersion();
  final DefaultVersionService.HybridLogicalTimestamp send1 = v.nextVersion();
  // when our physical clock is stuck, only the counter moves forward
  assertEquals(send.logicalTime(), send1.logicalTime());
  assertTrue(send.counter() < send1.counter());
  assertSame(send.counter(), send1.counter() - 1);
}