Core dumped when running pytest

I created PR for some Python project which uses Pytest for tests. However, my tests always fail even if the failure doesn’t seem to be related to my changes.

My PR is HelloZeroNet/ZeroNet#2164 and branch with my changes is filips123/ZeroNet@ethereum-name-service.

However, tests always fail with “core dumped” error:

src/Test/[ipv4] /home/travis/.travis/functions: line 109:  4580 Aborted                 (core dumped) python -m pytest src/Test --cov=src --cov-config src/Test/coverage.ini
The command "python -m pytest src/Test --cov=src --cov-config src/Test/coverage.ini" exited with 134.

This happens on all Python versions since 3.6 and log output is available here.

Note that CI status on GitHub PR is not latest as I tried to restart builds, but I did this on my repository, so status was not updated. However, the problem still persists. The complete build is available here. Note that failure on Python 3.4 and 3.5 is not related to this problem, as it is because of dependencies which do not support that Python versions. But failure on other Python versions is unexpected and shouldn’t happen.

The last test before the error was src/Test/[ipv4] which is available here. But I don’t know why it causes the error and it also works on original repository without my changes and my other branches without those changes.

Can you check what causes the error? Thank you.