Ruleset::processRuleset(): add tests for handling <autoload> directives

[jrfnl]

Description

Add tests specifically aimed at verifying <autoload> elements are read and handled correctly.

Note: as autoload directives are not stored in the ruleset, but directly lead to a file include using include_once, these tests need to run in a separate process to circumvent the possibility of test cross-contamination.

Suggested changelog entry

N/A

Related issues/external references

This PR is part of a series of PRs expanding the tests for the Ruleset class.

[rodrigoprimo]

LGTM!

I just wonder if you considered adding a path to the XML file that triggers the code on the line below:

PHP_CodeSniffer/src/Ruleset.php

Line 531 in 9c8f30f

$autoloadPath = $relativePath;

It seems to me that all the provided paths are making Common:realpath() returns false, and so the line that I mentioned is never executed.

[jrfnl]

I just wonder if you considered adding a path to the XML file that triggers the code on the line below:

PHP_CodeSniffer/src/Ruleset.php

Line 531 in 9c8f30f

$autoloadPath = $relativePath;

It seems to me that all the provided paths are making Common:realpath() returns false, and so the line that I mentioned is never executed.

Probably won't surprise you that I did consider it, I just needed some time to investigate what was going on a little more. Done that now, see the new commit.

[jrfnl]

Thanks for reviewing this @rodrigoprimo !