@Override
      public Object call() {
        try {
          getCache().getCacheTransactionManager().commit();
          fail("expected exception not thrown");
        } catch (TransactionInDoubtException ignored) {
        }
        Region<CustId, Customer> pr = getCache().getRegion(CUSTOMER);
        assertFalse(pr.containsKey(key));
        return null;
      }
test has a client, two accessors and a datastore pool connects to two accessors. we then close
the server in first accessor and verify failover
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ClientServerTransactionDUnitTest.java