Major Description
As part of SOLR-6349, i wanted to take advantage of the new features in SOLR-7147 to inspect shard requests in TestDistributedSearch, but even though i added a proper override of getSolrXml...
@Override protected String getSolrXml() { return "solr-trackingshardhandler.xml"; }
...that value was being ignored, and i was never getting an instance of TrackingShardHandlerFactory.
I poked around a bit and confirmed that getSolrXml() is used by "setupJettySolrHome(File)" but that method is never called by BaseDistributedSearchTestCase - it's only called in framework subclasses like AbstractDistribZkTestBase and AbstractFullDistribZkTestBase. Instead, for simple subclasses of BaseDistributedSearchTestCase the jetty instances seem to be coming from createServers(int)
I don't really understand why there are so many diff ways for a shard instance to be inited, and presumably that should be refactored? .. but a more immediate concern is that subclasses of BaseDistributedSearchTestCase which attempt to override the solr.xml file used can't (unless they are actually a subclass of AbstractDistribZkTestBase of AbstractFullDistribZkTestBase)