This introduces the following new comparison keys in `TestCase.assertQueries()`: * `limit` - The value for a SQL `LIMIT` * `offset` - The value for a SQL `OFFSET` * `select_for_update` - Whether `model.select_for_update(...)` was used * `values_select` - Any fields passed to `.values()` or `.value_list()`. It also does a few other things to fix and aid in comparisons. Any values in `extra` are now normalized. Whitespace is collapsed and stripped. Unit tests no longer have to be aware of the exact formatting of the SQL, which helps for more complex statements. Queries that are generated but not executed (any that would raise a `EmptyResultSet`) are now skipped for comparison. An example would be a query on `pk__in=[]`, which Django knows makes no sense to pass to the database. This is a way that code can short-circuit and optimize out an entire query or a particular clause of the query in Django. `assertQueries()` now ignores it just as Django does.