pytest-runner deprecated

[0-wiz-0]

This project still uses pytest-runner, but the upstream repository is archived:

Deprecation Notice

pytest-runner depends on deprecated features of setuptools and relies on features that break security mechanisms in pip. For example 'setup_requires' and 'tests_require' bypass pip --require-hashes. See also https://github.com/pypa/setuptools/issues/1684.

It is recommended that you:

    Remove 'pytest-runner' from your setup_requires, preferably removing the setup_requires option.
    Remove 'pytest' and any other testing requirements from tests_require, preferably removing the tests_requires option.
    Select a tool to bootstrap and then run tests such as tox.

[justinmk]

Any chance you can send a PR?

[0-wiz-0]

Take a look at #573, I think that's sufficient.