@Override
  public Properties getDistributedSystemProperties() {
    Properties props = super.getDistributedSystemProperties();
    if (xmlFile != null) {
      props.setProperty(CACHE_XML_FILE, xmlFile.toString());
    }

    // make it a loner
    if (lonerDistributedSystem) {
      props.setProperty(MCAST_PORT, "0");
      props.setProperty(LOCATORS, "");
    }

    return props;
  }
The version of GemFire tested by this class. This method should be overridden by subclasses.

@return version of GemFire tested by this class
@see CacheXml#VERSION_3_0
geode-dunit/src/main/java/org/apache/geode/cache30/CacheXmlTestCase.java