I pushed a patch d/patches/fix_python3_tests whic fixes almost all test issues(python3 related)
BUT remains a failing test with mason2 which is not related to py3 issue (no bytes-like error) after build, can be reproduced with in a temp dir: python3 /<<PKGBUILDDIR>>/apps/mason2/tests/run_tests.py /opt/debian/build-area/seqan2-2.4.0+dfsg /<<PKGBUILDDIR>>/obj-x86_64- linux-gnu/ it basically compare some generated files with some comparison files and for mason2 they are different, and program itself raise no error but result not as expected. Seems that many sequences output result are shifted by 1 character -- gpg key id: 4096R/326D8438 (keyring.debian.org) Key fingerprint = 5FB4 6F83 D3B9 5204 6335 D26D 78DC 68DB 326D 8438