Problem/Motivation
Automated tests greatly increase the size of a bare Drupal installation on disk. (As of 609912bced (8.8.x, July 15, 2019), they accounted for 43M of 94M (46%).) And they provide no benefit to end users in production. Indeed, they can contribute to security vulnerabilities and other problems. The number and size of files can also be a problem for users of shared hosting (c.f. #2338671: Create a smaller Drupal core download, removing tests, for production sites.), and they needlessly increase download and transfer times and disk usage for everyone, including drupal.org.
Proposed resolution
Use the approach documented in Use gitattributes to keep your tests out of other people’s production to exclude all tests/ directories from release packages. Since the Drupal.org packaging system already uses git-archive to create releases, the change would involve nothing more than the addition of a few lines to our .gitattributes file and would take effect immediately. Note: This would have no effect on Git clones, so neither the testbot nor core contributors would be affected.
Remaining tasks
- Consider possible unintended consequences.
- Review/test (forthcoming) patch.
- Probably write a change notice.
- Decide when to commit/release the change.
User interface changes
If tests can be considered to belong to the user interface in any sense, the change is that they will disappear from tarballs.
Release notes snippet
TBD.