QueryUtils

Check the types of things query objects should be able to do.

Various query sanity checks on a searcher, some checks are only done for instanceof IndexSearcher.

Check that the scorer and bulk scorer advance consistently.

Check that counting hits through DocIdStream.count yield the same result as counting naively.

deep check that explanations of a query 'score' correctly

check that first skip on just created scorers always goes to the right doc

check very basic hashCode and equals

alternate scorer advance(),advance(),next(),next(),advance(),advance(), etc and ensure a hitcollector receives same docs and scores

Given an IndexSearcher, returns a new IndexSearcher whose IndexReader is a MultiReader containing the Reader of the original IndexSearcher, as well as several "empty" IndexReaders -- some of which will have deleted documents in them. This new IndexSearcher should behave exactly the same as the original IndexSearcher.