add tests for migration
add tests for migration

learningequality/kolibri,mrpau/kolibri,lyw07/kolibri,indirectlylit/kolibri,indirectlylit/kolibri,benjaoming/kolibri,learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,benjaoming/kolibri,benjaoming/kolibri,mrpau/kolibri,learningequality/kolibri,lyw07/kolibri,indirectlylit/kolibri,lyw07/kolibri,lyw07/kolibri,benjaoming/kolibri