@Test
  public void testWarmUpConnectionsFailedAll() {
    selector.setState(MockSelectorState.FailConnectionInitiationOnPoll);
    List<ResponseInfo> responseInfos = new ArrayList<>();
    Assert.assertEquals("Connection count is not expected", 0,
        networkClient.warmUpConnections(localPlainTextDataNodes, 100, TIME_FOR_WARM_UP_MS, responseInfos));
    // verify that the connections to all local nodes get disconnected
    Assert.assertEquals("Mismatch in timeout responses", localPlainTextDataNodes.size() * MAX_PORTS_PLAIN_TEXT,
        responseInfos.size());
    selector.setState(MockSelectorState.Good);
  }
Test connection warm up failed case.
ambry-network/src/test/java/com/github/ambry/network/SocketNetworkClientTest.java