Bug#1061853: ttconv doesn't run any tests during the build and as autopkg test

[Matthias Klose]

Control: severity -1 serious

   dh_auto_test -i -O--buildsystem=pybuild
I: pybuild base:240: cd /<<PKGBUILDDIR>>/.pybuild/cpython3_3.10/build; 
python3.10 -m unittest discover -v

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK



this will fail with Python 3.12, exiting with value 5.

Please discover the tests properly.