Test suite and build environment had several issues with Pytest >3.6 which can be fixed by applying the (yet unreleased) upstream patch from f94b6940e3.patch
f94b6940e3
Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools. This update was made based on information from https://repology.org/metapackage/python3.6-pytest-repeat/versions
- compatible with 2.7, 3+ - all tests pass and running