@Override
  public final void postSetUp() throws Exception {
    previousMemoryEventTolerance =
        System.setProperty(GeodeGlossary.GEMFIRE_PREFIX + "memoryEventTolerance", "1");
    disconnectAllFromDS();
  }
set this to false if a test needs a non-loner distributed system
geode-dunit/src/main/java/org/apache/geode/cache30/CacheXmlTestCase.java