Do you have a test-set with xquery-statements?
You could have a look at the official QT3 test suite
https://github.com/w3c/qt3tests
30.000 tests should be enough I hope ;) You find additional BaseX-specific tests (for XQUF, XQFT, edge cases) in our JUnit tests:
https://github.com/BaseXdb/basex/tree/master/basex-core/src/test/java/org/ba...