What is the test for good faith in performing a public duty?

The general requirement of good faith in performing a public duty was set out in Roncarelli v. Duplessis, 1959 CanLII 50 (SCC), [1959] S.C.R. 121 at p. 143 as follows: ‘Good faith’ in this context...means carrying out the statute according to its intent and for its purpose; it means good faith in acting with a rational appreciation of that intent and purpose and not with an improper intent and for an alien purpose; it does not mean for the purposes of punishing a person for exercising an unchallengeable right; it does not mean arbitrarily and illegally attempting to divest a citizen of an incident of his civil status.