Correct tests for export mode
Correct tests for export mode

The old tests were wrong but the incorrectness was hidden by the incorrect
parameter passing fixed in the previous commit. Now we actually test that the
item's path did not change.

SusannaMaria/beets,shamangeorge/beets,pkess/beets,beetbox/beets,shamangeorge/beets,ibmibmibm/beets,SusannaMaria/beets,jackwilsdon/beets,shamangeorge/beets,beetbox/beets,beetbox/beets,sampsyo/beets,SusannaMaria/beets,ibmibmibm/beets,sampsyo/beets,jackwilsdon/beets,jackwilsdon/beets,pkess/beets,shamangeorge/beets,sampsyo/beets,pkess/beets,jackwilsdon/beets,pkess/beets,ibmibmibm/beets,beetbox/beets,sampsyo/beets,ibmibmibm/beets,SusannaMaria/beets