private static void createRegion() throws Exception {
    HARegionQueueDUnitTest test = new HARegionQueueDUnitTest();
    cache = test.createCache();
    AttributesFactory factory = new AttributesFactory();
    factory.setScope(Scope.DISTRIBUTED_ACK);
    factory.setDataPolicy(DataPolicy.REPLICATE);

    // Mock the HARegionQueue and answer the input CachedDeserializable when updateHAEventWrapper is
    // called
    HARegionQueue harq = mock(HARegionQueue.class);
    when(harq.updateHAEventWrapper(any(), any(), any()))
        .thenAnswer(AdditionalAnswers.returnsSecondArg());

    HARegion.getInstance("HARegionQueueDUnitTest_region", cache, harq,
        factory.create(), disabledClock());
  }
create a client with 2 regions sharing a common writer
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ha/HARegionQueueDUnitTest.java