Support exploring metadata from Python source code

[psss]

@jscotka has experimented with storing fmf metadata using decorators directly in the Python code:

• https://github.com/jscotka/fmf_metadata

It could be useful to add support for such parsing directly to fmf. By default, *.fmf files would be checked only, a dedicated option could be used to enabled parsing *.py files as well.

fmf --extension py

Metadata could be combined from both sources:

fmf --extension fmf --extension py

In tmt the discover step could support a relevant option to enable such behaviour:

discover:
    how: fmf
    extension: [fmf, py]

Just the first brainstorm of possible syntax...

[jscotka]

After small brainstorming, that would be also nice that FMF could use any file with metadata, although inside code, be able to find special prefixed strings inside comments like: runtest.sh

#!/bin/bash
# :FMF: summary: This is a summary of the test
# :FMF: duration: 1m
# :FMF: environment+: {TEST_OS: linux}

/bin/true

will seems like FMF file: runtest.sh.fmf

summary: This is a summary of the test
duration: 1m
environment+: {TEST_OS: linux}

and it can work like searching strings inside file re.search(":FMF:(\1)", line).group(1)
but theoretically, it would be harder when using virtual hierarchy

• with parametrized tests
• more tests in one file like python unittest
  in this case, it is important to know the test structure and semantics of the language.

this could be covered by semantics for structure like # :FMF /path1/path2: summary+: extension where it structures summary structure like path1:{ path2: {summary }}

so something like python docstring still possible, but harder to use, or better to say, important to write semantics for every language we want.

But as the opposite side, I like the idea of decorators, because there works automatic completion, semantics check, so it is clean and well structured as python code

[jscotka]

done question to pytest upstream, if able to do external python exploring:

pytest-dev/pytest#8554

EDIT:
solved and solution is finally easy to collect all pytest test

[jscotka]

PoC inside FMF: #136
it uses code from my fmf_metadata project and it allows to do plugin for any language/framework what you want.