testing save:

1 - create a file, set its contents to "foo", open it in gedit, set the contents to "bar", save it, check the contents is "bar", check if the backup file is created and if it properly contains "foo"
2 - like 1, but using each one of the available encodings (the contents has to contain unicode characters instead of "bar")
3 - like 1, but before opening chmod the file (in a way that it is still writable), upon saving check perms are preserved
4 - like 1, but before opening chown the file (in a way that it is still writable), upon saving check ownnership is preserved
5 - like 1, but with a writable file inside a non writeable directory
6 - like 1, but with the file being a symlink
7 - like 1, but with the file being a hardlink
8 - like 3, 4 and 5, but with the file being a symlink

repeat all of the above with "keep backup file" disabled, check the backup is properly deleted
repeat all the above for sftp, ftp, etc uris

(Note: current version of gedit doesn't yet pass some of the above, like 3 and 4 and all the remote vfs writing)