Currently nightwatch plugin was a poc for just core. Now that its in core, contrib is already trying to use it.
https://www.drupal.org/project/autodrop/issues/2972588 → is an example.
We'll need to feed it the start directory by adding DRUPAL_NIGHTWATCH_SEARCH_DIRECTORY to the env config directory.
Fixed
Testrunner Codebase
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.