Drupal\field\Tests\reEnableModuleFieldTest apparently "tests a field is still present after it's module is disabled then re-enabled" according to its name and comment - but it can't actually do this as we can't disable or re-enable modules any more.
The only thing it actually seems to do is test the "field types in use" and "fields pending deletion" text on the modules page by adding a field and then deleting it.
Comments
Comment #1
swentel commentedThis is being handled in #2080823: Create API to discover config entities' soft dependencies and use this to present a confirm form on module uninstall
Comment #2
swentel commentedSo #2080823: Create API to discover config entities' soft dependencies and use this to present a confirm form on module uninstall got refocused, but we still have #2198429: Make deleted fields work with config synch - will update this after we have our hangout discussion about that one today.