Migrate D7 block_class to D8/D9

I have created an MR , please merge . Thanks

Thanks a lot everyone for your great help on this issue and sorry for the delay of this reply.

Quick follow-up:
Easily rebased MR!11 and started running the tests locally on D10.
I quickly noticed the fixtures were based on themes bartik and seven which have been removed in core D10 and moved to contrib.

After adding the themes locally with composer, the tests ran successfully without any change to the work from #4!
Great job getting some tests added!

Lastly, for D11 (phpunit next major), adding the bartik and seven themes with composer was not an option since they don't seem to have compatible versions at this moment, see:

• Bartik: 📌 Automated Drupal 11 compatibility fixes for bartik Needs review
• Seven: 📌 Automated Drupal 11 compatibility fixes for seven Needs review

 
Therefore, the D7 Migrate Kernel Tests had to be disabled/excluded temporarily for D11.
 
The changes have been merged in the 8.x-1.x branch at #12, thus marking this issue as Fixed for now.
 
Feel free to let us know if you have any questions, suggestions or concerns on any of the recent code changes or this ticket in general, we would be glad to help!
 
Thanks again everyone for the great work and contributions!

Automatically closed - issue fixed for 2 weeks with no activity.