Fix test decorator for PyLinter options

[DanielNoord]

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Type of Changes

	Type
✓	🐛 Bug fix

Description

I stumbled upon this while working on #5194.

Without this we don't actually set settings that come from PyLinter correctly and therefore we can't test them with get_global_option.
This should pass tests immediately, but if not I will fix them!

[Pierre-Sassoulas]

Shouldn't this be done in make_options directly ? It's hard to know you need to do that after calling, we may as well do it all the time automatically ?

[DanielNoord]

The decorator now handles three cases "correctly".

1. If the option is from the checker that is loaded by the unittest class, it sets the setting using the normal validator and flow
2. If the option is from PyLinter, it sets the setting using the validator by getting the optdict from PyLinter
3. If the option is from another checker, it sets the setting using a shortcut. It doesn't create an optdict but is allowed to set the setting

The initial change I did some weeks ago was to allow both 2 and 3, but it turned I should have separated those cases more clearly.

Investing more time in 3 and allowing double-loading of checkers during unittests does not seem worth the effort. If we are going to rework the config handling because of optparse's deprecation anyway, we might as well leave this hacky trick. It's only for our own tests and it is already much better than the decorator we used a couple weeks ago.

[coveralls]

Pull Request Test Coverage Report for Build 1369823526

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 93.25%

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Totals
Change from base Build 1360083361:	0.001%
Covered Lines:	13635
Relevant Lines:	14622

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💛 - Coveralls

[DanielNoord]

Shouldn't this be done in make_options directly ? It's hard to know you need to do that after calling, we may as well do it all the time automatically ?

make_options is only used twice. Once to merge (I think) command line options with options from PyLinter itself. See L528 in the PyLinter file. For this use we don't need to pass a key as we are expecting it to just return the options dict.

https://github.com/PyCQA/pylint/blob/259f7a381d19bdbfaa84343825e0638323aed55f/pylint/lint/pylinter.py#L527-L528

The other use is on this decorator. Basically we want to call PyLinter.options, but since we can't (since we use UnittestLinter instead of the normal linter) we need to call the constructor of PyLinter.options. Afterwards we immediately pass the key, because we know which optdict we want to "read".

[Pierre-Sassoulas]

👍