Allow to work with PHPUnit 10

[Jean85]

This draft of a PR was needed for me to work on PHPUnit 10 compat on another project, see facile-it/paraunit#172

It allows two packages to the next major version (5), with no other code modifications since there are no BC impacting Prophecy.

[stof]

Can you rebase your branch to avoid the merge commit ?

Also, is this actually a draft PR ?

[Jean85]

Rebased.

I left it as draft since both majors of both packages are not released yet.

[stof]

@sebastianbergmann is it safe for us to release this change now or do you expect to do more BC breaks in sebastian/comparator and sebastian/recursion-context before their stable 5.0 release ?

[sebastianbergmann]

I consider any such changes highly unlikely.

[Jean85]

@sebastianbergmann @stof I've found a BC that's hitting this PR and it's going unnoticed due to the CI here not installing a dev dep: SebastianBergmann\Comparator\Factory if final and it's being extended in Prophecy\Comparator\Factory.

We could easily fix it with the decorator patter, but I don't know if it's to be considered a BC here (since no longer extending the class).

[stof]

@Jean85 you need to update the specs of that Factory

[Jean85]

@stof I didn't do it because, apart from the fact that I'm not skilled with PHPSpec, I'm not sure on how to proceed:

• one test asserts that the class should extend the PHPUnit's one (should I change it to "not"? Should I expect it on the returned, decorated factory?)
• The other one tests the behavior, which is changed...

[stof]

I worked on preparing this work in #589

[Jean85]

Rebased to include #589

[Jean85]

Closing and reopening to trigger a CI run, now that PHPUnit 10 is released.

[Jean85]

This would require phpspec/phpspec#1443 to test and work completely.

[Jean85]

Let's follow the suggestion from phpspec/phpspec#1443 (comment) and test on an optional CI job requiring master.