static String getTagValue(CassandraStorage storage, String key) {
    return storage
      .session()
      .execute("SELECT value from " + Schema.TABLE_AUTOCOMPLETE_TAGS + " WHERE key='" + key + "'")
      .one()
      .getString(0);
  }
It is easier to use a real Cassandra connection than mock a prepared statement.
zipkin-storage/cassandra/src/test/java/zipkin2/storage/cassandra/ITSpanConsumer.java