What is the test for the doctrine of forum non conveniens?

… When it is invoked, the doctrine of forum non conveniens requires a court to go beyond a strict application of the test governing the recognition and assumption of jurisdiction. It is based on a recognition that a common law court retains a residual power to decline to exercise its jurisdiction in appropriate, but limited, circumstances in order to assure fairness to the parties and the efficient resolution of the dispute. The court can stay proceedings brought before it on the basis of the doctrine. See also: Haaretz.com v. Goldhar, 2018 SCC 28 at paras. 26–32, [2018] 2 S.C.R. 3.