Automated tests for files_versions

[PVince81]

The app doesn't have public endpoints but we could use the private ones in the time being.

Tests like:

• overwriting a file multiple times creates versions
• version can be downloaded and contains the old content
• file can be restored to old version, download it contains the old content
• preview correctly returned (no error) for the version file (same URL as rendered in versions panel)
• restoring a version still works if no delete permission on target file
• all of the above with trashbin: delete a file that has versions, restore the file and check that the versions still work (download/restore)
• all of the above with encryption (including the trashbin one)
• all of the above with received shared files

@owncloud/qa

[PVince81]

Some tricky bits:

• finding out the name of a version that has just been created
• versions might not be created accurately / in a predictable manner, which could cause random test failures

[PVince81]

@phil-davis can you take over and mark those already implemented ?

[phil-davis]

Assigned myself so that I find this! Needs a review of what is already in the acceptance tests, then make a list of what is remaining to test...