public static String getLocatorString(int[] locatorPorts) {
    String locatorString = "";
    int numLocators = locatorPorts.length;
    for (int i = 0; i < numLocators; i++) {
      locatorString += getLocatorString(locatorPorts[i]);
      if (i + 1 < numLocators) {
        locatorString += ",";
      }
    }
    return locatorString;
  }
This test starts up multiple servers from the current code base and multiple servers from the
old version and executes puts and gets on a new server and old server and verifies that the
results are present. Note that the puts have overlapping region keys just to test new puts and
replaces
geode-core/src/upgradeTest/java/org/apache/geode/internal/cache/rollingupgrade/RollingUpgrade2DUnitTestBase.java