Add documentation for primer and convert to command line option

[DanielNoord]

• Add yourself to CONTRIBUTORS if you are a new contributor.
• Write a good description on what the PR does.

Type of Changes

	Type
✓	✨ New feature
✓	🔨 Refactoring
✓	📜 Docs

Description

Based on https://docs.pytest.org/en/latest/example/simple.html#control-skipping-of-tests-according-to-command-line-option

Because we can remove the standard addopts IDEs like VS Code will now actually find all tests in our test suite, but will just skip them when running normally. Makes it easier (at least for those on VS Code) to explore all tests.

Ticks of two points from #5306

[coveralls]

Pull Request Test Coverage Report for Build 1502943571

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 93.499%

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Totals
Change from base Build 1500123956:	0.0%
Covered Lines:	13995
Relevant Lines:	14968

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💛 - Coveralls

[Pierre-Sassoulas]

Suggested change

	"--primer_stdlib",
	"--primer-stdlib",

[DanielNoord]

You can't mark with @pytest.mark.primer-stdlib so I thought I would keep consistency throughout the functions using it. Do you want me to change it anyway?

[Pierre-Sassoulas]

For CLI option I think the standard is -

[Pierre-Sassoulas]

Suggested change

	"--primer_external",
	"--primer-external",

There's a lot of other place to change, but it's hard to do in github.

[DanielNoord]

We still need to add the mark to the pytest command as otherwise the CI job will run all tests including the primer. I think the latest commit fixes the increased run time of primer in this PR.

[Pierre-Sassoulas]

We still need to add the mark to the pytest command as otherwise the CI job will run all tests including the primer

Wasn't the point of adopt that primer were not launched by default ? What am I missing ?

[DanielNoord]

We still need to add the mark to the pytest command as otherwise the CI job will run all tests including the primer. I think the latest commit fixes the increased run time of primer in this PR.

This has been fixed with dab1e03

Wasn't the point of adopt that primer were not launched by default ? What am I missing ?

With this implementation --primer-external is False by default. It looks in the item.keywords (decorators) and if primer_stdlib is in there it adds a skip. If the option is supplied this won't happen so the mark isn't skipped. We need to add -m primer_external to then tell it to only run the marked tests again.

Basically instead of not selecting the mark by default (and therefore not showing up in test collection) this makes it so the mark is skipped by default.