What is the legal test for professional membership of a professional association?

It is clear from the evidence that the persons giving the advisory or consulting service here are highly skilled professionals. In Montgomery v. M.N.R., [1996] 1 C.T.C. 2796, revised 1997 CanLII 5657 (FC), [1998] 1 C.T.C. 58, restored 1999 CanLII 7732 (FCA), [1999] 2 C.T.C. 196, the following observation was made: Equally I think that it is clear that the annual membership dues paid by him are “professional” membership dues. We have come a long way from the days when the only recognized professions were the clergy and the military. Somewhat later law and medicine became recognized as “professions”. Since that time the expression has come to cover a vast variety of callings: dentists, land surveyors, artists, ministers, teachers, nurses, secretaries, dancers, therapists, scientists, accountants, professors, social workers, druggists, engineers, computer specialists, and writers to mention only a few that come to mind.