@Test
  public void testRollLocatorsWithOldServer() {
    final Host host = Host.getHost(0);
    VM locator1 = host.getVM(sourceConfiguration, 0);
    VM locator2 = host.getVM(sourceConfiguration, 1);
    VM server4 = host.getVM(sourceConfiguration, 3);

    int[] locatorPorts = AvailablePortHelper.getRandomAvailableTCPPorts(3);
    locator1.invoke(() -> DistributedTestUtils.deleteLocatorStateFile(locatorPorts));
    locator2.invoke(() -> DistributedTestUtils.deleteLocatorStateFile(locatorPorts));

    String hostName = NetworkUtils.getServerHostName();
    String locatorString = getLocatorString(locatorPorts);
    try {
      locator1.invoke(invokeStartLocator(hostName, locatorPorts[0], getTestMethodName(),
          getLocatorProperties(locatorString), true));

      // Locators before 1.4 handled configuration asynchronously.
      // We must wait for configuration configuration to be ready, or confirm that it is disabled.
      locator1.invoke(
          () -> await()
              .untilAsserted(() -> assertTrue(
                  !InternalLocator.getLocator().getConfig().getEnableClusterConfiguration()
                      || InternalLocator.getLocator().isSharedConfigurationRunning())));

      locator2.invoke(invokeStartLocator(hostName, locatorPorts[1], getTestMethodName(),
          getLocatorProperties(locatorString), false));

      invokeRunnableInVMs(invokeCreateCache(getSystemProperties(locatorPorts)), server4);

      locator1 = rollLocatorToCurrent(locator1, hostName, locatorPorts[0], getTestMethodName(),
          locatorString);
      locator2 = rollLocatorToCurrent(locator2, hostName, locatorPorts[1], getTestMethodName(),
          locatorString);

    } finally {
      invokeRunnableInVMs(true, invokeStopLocator(), locator1, locator2);
      invokeRunnableInVMs(true, invokeCloseCache(), server4);
    }
  }
starts 3 locators and 1 server rolls all 3 locators and then the server
geode-core/src/upgradeTest/java/org/apache/geode/internal/cache/rollingupgrade/RollingUpgradeRollLocatorsWithOldServer.java