In theory, the tests can be run with no problem. Sometimes there is one that randomly fails (regarding thesauri) but another run clean usually fix the problem. It happens more often in my local computer than in Travis, so I think it has to do with a non clean environment.
The integration tests are something still experimental but yes, in theory they should pass. Haven't check yet personally with latest build. Until we incorporate them to Travis, there is no way to warrantee they will always pass.