Add unit test for the TreeModelSort override
Add unit test for the TreeModelSort override

GNOME/pygobject,davibe/pygobject,pexip/pygobject,davibe/pygobject,MathieuDuponchelle/pygobject,MathieuDuponchelle/pygobject,sfeltman/pygobject,MathieuDuponchelle/pygobject,pexip/pygobject,sfeltman/pygobject,GNOME/pygobject,davibe/pygobject,GNOME/pygobject,sfeltman/pygobject,pexip/pygobject,davibe/pygobject