Cover checkboxes of an array field mixed with disabled ones

[Amoifr]

This is step 1 of the plan @aik099 laid out in minkphp/MinkBrowserKitDriver#150: cover the handling of disabled checkboxes, which nothing in the suite does today. multicheckbox_form.html has two checkboxes sharing an array name and neither is disabled.

The new fixture mirrors the report: two disabled checkboxes, one of them checked, followed by two enabled ones. That ordering is the interesting part, since a driver that numbers the fields differently than the browser does ends up manipulating the wrong checkbox, or none at all.

One thing worth saying before anyone re-runs the driver builds: the BrowserKitDriver bug this comes from is already gone, and this test passes there (168 tests green). It was never a driver bug. Form::addField() in dom-crawler 4.4.5 returned early for disabled nodes, so they were missing from the form array while getFieldPosition() still counted them in the DOM. symfony/symfony#35937 reverted that on 2020-03-03 and shipped it in 4.4.6, moving the disabled check into getValues()/getFiles() where it belongs. The issue was opened 13 days after that release.

So this is a regression guard rather than a failing test: it locks the behaviour in so a future change upstream cannot reintroduce it silently. I have no way to run the Selenium-based drivers, so if one of them turns out to disagree with the assertions, tell me and I will adjust them.

I added a separate fixture instead of touching multicheckbox_form.html, since other drivers have tests bound to its exact contents.

[stof]

The CI static analysis job is fixed by #114. Rebasing your branch should make it pass.

[Amoifr]

Rebased on master, so #114 is in. PHPStan is clean locally on the rebased branch, thanks for the pointer.

[stof]

I triggered new CI runs on our 3 drivers:

• https://github.com/minkphp/MinkSelenium2Driver/actions/runs/33735759176
• https://github.com/minkphp/MinkBrowserKitDriver/actions/runs/33735788641
• https://github.com/minkphp/webdriver-classic-driver/actions/runs/33735826966

All drivers are passing those new tests