public static synchronized void beginCacheXml() {
    closeCache();
    cache = new TestCacheCreation();
  }
Sets this test up with a {@code CacheCreation} as its cache. Any existing cache is closed.
Whoever calls this must also call {@code finishCacheXml}.
geode-dunit/src/main/java/org/apache/geode/test/dunit/cache/internal/JUnit4CacheTestCase.java