@Test
  public void testIsolatedDistributedSystem() throws Exception {
    Properties config = createLonerConfig();
    InternalDistributedSystem system = getSystem(config);

    // make sure isolated distributed system can still create a cache and region
    Cache cache = CacheFactory.create(system);
    Region region = cache.createRegion(getUniqueName(), new AttributesFactory().create());
    region.put("test", "value");

    assertThat(region.get("test")).isEqualTo("value");
  }
Tests getting a system with a different configuration after another system has been closed.
geode-core/src/distributedTest/java/org/apache/geode/distributed/DistributedSystemDUnitTest.java