What is the test for "mootness"?

In Borowski v. Canada (Attorney General), 1989 CanLII 123 (SCC), [1989] 1 S.C.R. 342 at 353, Justice Sopinka, writing for the court, described the correct approach to the issue of mootness: The approach in recent cases involves a two-step analysis. First it is necessary to determine whether the required tangible and concrete dispute has disappeared and the issues have become academic. Second, if the response to the first question is affirmative, it is necessary to decide if the court should exercise its discretion to hear the case. The cases do not always make it clear whether the term “moot” applies to cases that do not present a concrete controversy or whether the term applies only to such of those cases as the court declines to hear. In the interest of clarity, I consider that a case is moot if it fails to meet the “live controversy” test. A court may nonetheless elect to address a moot issue if the circumstances warrant.