If you run the tests, the final testsuite exercises the XSLT engine and it will list a number of failures. Quite a large number. XSLT development is ongoing, and I'm using the OASIS XSLT test suite to guide that. Consequently, the tests that fail generally indicate something I haven't done yet, rather than an actual bug. The XSLT tests are, therefore, ignored by
make check (should you be lucky enough to be working on a Unixy platform).
Failures in any other tests are, however, indicative of a problem that needs investigating.