@Override
      public HelixManager getZKHelixManager(String clusterName, String instanceName, InstanceType instanceType,
          String zkAddr, ClusterMapConfig clusterMapConfig1) {
        return mockHelixManager;
      }
Test that replica is correctly disabled when store is shut down due to disk I/O error.
@throws Exception
ambry-store/src/test/java/com/github/ambry/store/BlobStoreTest.java