add unit test for user owned_by plan method
add unit test for user owned_by plan method

(cherry picked from commit ad801defd54a49a48e7ba797b897a265383931af)

CDLUC3/roadmap,CDLUC3/dmptool,CDLUC3/roadmap,DMPRoadmap/roadmap,CDLUC3/roadmap,DMPRoadmap/roadmap,CDLUC3/dmptool,CDLUC3/roadmap,CDLUC3/dmptool,DigitalCurationCentre/roadmap,DigitalCurationCentre/roadmap,DigitalCurationCentre/roadmap,CDLUC3/dmptool,DMPRoadmap/roadmap