Unify handling of requirements annotation to be handled completely by phar-io/version

[dnaber-de]

Q	A
PHPUnit version	> 6.* (unreleased patch)
PHP version	7.*
Installation Method	Composer

The changes made for #2386 introduces some »overhead« in order to maintain backward compatibility. For the next major release (probably version 7) PHPUnit\Util\Test allows some backward incompatible improvements.

Suggested updates

• Combine both regular expressions PHPUnit\Util\Test::REGEX_REQUIRES_VERSION and PHPUnit\Util\Test::REGEX_REQUIRES_VERSION_CONSTRAINT to cover all possible version constraints
• Combine the structure of the requirements array created by PHPUnit\Util\Test::getRequirements(): $requirements['PHP_constraint'] and $requirements['PHP']
• Rely on phar-io/version API to handle version compliance check for every possible case

Update
Related pull request: #2623

[sebastianbergmann]

@dnaber-de Can you send a pull request that implements the proposed changes?

[dnaber-de]

Yes, I'll take some time on this next week.

[dnaber-de]

Sorry, it seems that I was to optimistic with my proposal.

Rely on phar-io/version API to handle version compliance check for every possible case

Right now, it can only compare constraints that contains the caret or tilde operator. Thus, there won't be much benefit in changing Tests::getRequirements() as Tests::getMissingRequirements() would still need to make a difference between constraints like >=7.0 and ^7.0.

I'll have a more detailed look into phar-io/version and maybe suggest an improvement over there. Suggest to close this ticket right now.