We are missing tests cover for upgrade.

For example here #1810 we had issue with admin menu.

I propose to create next tests: - check if menu structure is the same after upgrade - blocks is in place after upgrade - content is listed on pages - comments is listed on pages

any other ideas?

It should help with future testing to upgrade a version from stable to new.

GitHub Link: 
https://github.com/backdrop/backdrop-issues/issues/1874
GitHub Issue #: 
1874