Tests adapted to new default (empty) 'nbrmd_formats' mwouts/nbsrc#5
Tests adapted to new default (empty) 'nbrmd_formats' mwouts/nbsrc#5

mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext,mwouts/jupytext