Backup and restore with files references

Test Pre-requisites:

1. Login as admin/teacher, make sure at least two courses exist
2. Enable course legacy files for the first course
3. Add several files to your private files area, course legacy files and a folder activity, including images
4. Create an activity module, insert into description images from pre-requisite #3 as alias/shortcuts
5. Create a new folder resource and add files from pre-requisite #3 as alias/shortcuts

How to make sure that file is a reference:

• if the file is in filearea (i.e. file/folder resource), when you edit the filearea the "shortcut" icon is displayed near the file. When you click on file the information window shows the source location. If the file is embedded image - see below
• if you edit the filearea that has the source file (user private files or course legacy files), the source file has the "link" icon. When you click on file the information window shows the list of aliases/shortcuts in the system
• (double check) if you edit the filearea with the source and upload another file with the same name as the source and choose to overwrite, all alias/shortcuts will now show the new file (don't forget to save changes before checking!)

Test Steps:
1. Duplicate activities and resources created in pre-requisites #4 and #5.
2. Make sure that all files are still references.