1 more step to remove nose

[lasote]

Changelog: Feature: Changed recommended way to launch test suite, with pytest over nosetests.
Docs: Omit

Doesn't need docs, just README instructions

• Added pytest custom marks in addition to the current nose attrs.
• Changed readme and tox to use pytest as the recommended way.

What's next?

• We could change the Jenkins to use pytest, but until this is not in master branch it will fail, but would be necessary to somehow try it sooner.
• Introduce new/better marks so Proof of Concept of Testing with multiple tooling #7818 can be implemented.

Part of #6527

[memsharded]

Looks good!

[jgsogo]

In order to test it in the CI, I'd recommend to rename the Jenkinsfile and create a different multibranch project in Jenkins. It could also need a matching branch (using pytest) of the conan_ci library.

Existing Jenkins project will run the current Jenkinsfile with the current default conan_ci branch. New Jenkins project will be configured with the new Jenkinsfile and a different branch of the conan_ci library.

As this PR evolves or it is merged in develop, the old CI project will stop to run (no matching Jenkinsfile) and the new one will take care of pull-requests and changes. Eventually, when all PRs are rebased, we might consider using the previous default branch for conan_ci.

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Following this approach, we can remove the @attr(...) in this PR too, remove nose from the requirements,... and check it works with pytest.

[lasote]

I think it is easier to open first a PR in the Jenkins library to add a new function that will cause "pytest" to run instead of "nosetests". Then modify here the Jenkinsfile to call that. The "new pytest" library will keep evolving with new pipelines to run first only python tests, then tools, and so on (like the pictures at conan-io/conan_ci_jenkins#10) so when merged, It will be automatically enabled (on each branch). Eventually, we could remove the old library that launches nosetest.

[lasote]

Also, I think it is better to merge small chunks to avoid a gigantic PR. I'll fix the imports order and I vote to merge this to develop (because it doesn't affect anything but recommending to use pytests)

[memsharded]

Also, I think it is better to merge small chunks to avoid a gigantic PR. I'll fix the imports order and I vote to merge this to develop (because it doesn't affect anything but recommending to use pytests)

Yeah, I agree, we can go step by step, the CI job can an is better to be done in another PR.