What is the test for a court to exercise discretion in deciding whether or not to intervene in a civil matter?

However, before declining to exercise its discretion, the court must consider three factors - namely, the presence or absence of an adversarial context (that is, given that the parties no longer have a personal interest in the outcome of the issue, the court must be satisfied that the issue could be fully argued); the concern for judicial economy (that is, given the scarcity of judicial resources the court must be satisfied that time spent deciding this issue is justified - that it is an issue "capable of recurrence and evasive of review"); and the need of the courts "to be sensitive to the effectiveness or efficacy of judicial intervention and demonstrate a measure of awareness of the judiciary's role in our political framework" (that is, that the issue falls within the traditional role of the courts and does not intrude into the executive or legislative branches of government) (Borowski v. Canada (Attorney-General) (supra)).