Synonyms for Testy (same or very similar meaning)
WordNet sense 1 (easily irritated or annoyed):
cranky, fractious, irritable, nettlesome, peevish, pettish, petulant, scratchy, peckish, techy, tetchyWordNet sense 2 (having an irritable and unpleasant disposition):
ill-naturedFrom the ODE community, based on WordNetadd/edit