What is the test for security of tenure under the Charter of Canada?

Reference should also be made to Valente v. The Queen 1985 CanLII 25 (SCC), [1985] 2 S.C.R. 673 where at p. 694, Le Dain, J. said: Security of tenure, because of the importance that has traditionally been attached to it, must be regarded as the first of the essential conditions of judicial independence for purposes of Section 11(d) of the Charter. (See p. 694) The essence of security of tenure for the purposes of Section 11(d) is a tenure, whether until an age of retirement, for a fixed term, or for a specific adjudicative task, that is secure against interference by the Executive or other appointing authority in a discretionary or arbitrary manner. (See p. 698)