Prep work to migrate to PHPUnit 9.x

[sanmai]

This is a fully backward-compatible change.

The general idea is to make the package testable under PHP 5.6 - 7.x - 8.0. This requires using both PHPUnit 5.x and 9.x, because only the last works correctly under PHP 8 (as is - collects coverage report).

But PHPUnit 9 has quite a lot of legacy methods removed, and PHPUnit 8 has these methods but with void return type. Therefore implementing these methods straight away is a no-go. This can be with a version-dependent trait, but for a small handful of functions used here it easier to do this by overloading them from __call and __callStatic. This is where DeprecatedTestMethods trait comes into play.

And there are also setUp(): void etc. which are not taken care in this PR.

• There's also above-mentioned PolyfillAssertTrait from symfony/phpunit-bridge, but it is tagged @internal so it's a risky game to use it.
• And there's also phpunitgoodpractices/polyfill, but it should be trivial to switch to any of those down the line.

---

Extracted from #5262 (it handles setUp(): void among other things)

[sanmai]

@keradus should it be more appropriate to use phpunitgoodpractices/polyfill here instead of a purpose-build short polyfill?

[SpacePossum]

utilizing phpunitgoodpractices/polyfill would be great as more people found benefit from your work : )

(also we would have less maintenance in this project so I'm biased ;) )

[sanmai]

Good point. Give me a minute to sort this out.

[sanmai]

Should I add phpunitgoodpractices/polyfill as a direct dependency?

[keradus]

👍
feel free to raise PRs to that polyfill repo too, don't hesitate to reach out to me over https://gitter.im/keradus

[sanmai]

@keradus DM'ing you there!

[sanmai]

As of now phpunitgoodpractices/polyfill has none of the methods we need here. First PR for phpunitgoodpractices/polyfill is go PHPUnitGoodPractices/polyfill#16. Once there's a CI, I'll add other necessary methods.

Meanwhile this is ready for merge. Migrating to phpunitgoodpractices/polyfill will be as simple as removing one file and changing one line.

This is a blocker to #5262. Reviewing and merging this will let me to continue my work on #5262. Please consider this.

[keradus]

nice 👍

[GrahamCampbell]

What is the reason for the re-target?

[GrahamCampbell]

Oh, I see. The last 2.15.x release has just happened?

[GrahamCampbell]

So, what is the status with phpunitgoodpractices/polyfill? I think this is the only outstanding thing blocking merge now. The rest looks great, from what I can see.

[sanmai]

@GrahamCampbell what we're doing there is fairly tricky, and, considering that @keradus is, understandably, looking for an uncompromising quality, at these circumstances I'd like to see it getting as thorough review as possible. Therefore, we have to wait for it to happen.

[keradus]

nice one ;)

[sanmai]

Do I need to squash-rebase it? It's not a big deal, but squash merging will be easier.

[keradus]

squash doesn't matter.
i only await for CI to confirm it works on all supported combinations of phpunit

[GrahamCampbell]

This can be (squash) merged now, I think?

[keradus]

easy @GrahamCampbell , it will be merged when it will be merged. no need for pinging, especially when you see movement around related changes

[GrahamCampbell]

I wasn't rushing. I was just re-approving after the changes you just made. :)

[keradus]

Thank you @sanmai.