[dev] When to require, suggest or require-dev Re: PHPUnit 9.5 compat

[Ralf Lang]

Hello,


> A colleague and I began converting some library unit tests to phpunit 9.
>
> This meant

While upgrading the unit test for horde/date to github actions, phpunit
9, I stumbled across a little problem.

Some unit tests require but don't check for the horde/icalendar library.

https://github.com/maintaina-com/Date/runs/2141049425?check_suite_focus=true

Icalendar is only suggested for horde/date but no dependency.

What would be the right path here?

- make the icalendar library a require-dev
- install all suggests for unit testing
- Make the tests skip on missing optional dependency

-- 
Ralf Lang
Linux Consultant / Developer
Tel.: +49-170-6381563
Mail: lang at b1-systems.de
B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537