I had a look at the failing test. I think we can ignore ConcurrentMergeErrorHandledTest, but the sharding tests show a problem with the current approach. In the case of sharding we need multiple indexes for the documents, but only one taxonomy index. See also http://mail-archives.apache.org/mod_mbox/lucene-java-user/201301.mbox/%3CCALfq-2QkLJaLtbaH7P1_XARJYQju_Nd6QUK1CdvGXXPTsjRPQA@mail.gmail.com%3E
I had a look at the failing test. I think we can ignore ConcurrentMergeErrorHandledTest, but the sharding tests show a problem with the current approach. In the case of sharding we need multiple indexes for the documents, but only one taxonomy index. See also http://mail-archives.apache.org/mod_mbox/lucene-java-user/201301.mbox/%3CCALfq-2QkLJaLtbaH7P1_XARJYQju_Nd6QUK1CdvGXXPTsjRPQA@mail.gmail.com%3E