What are the legal tests for obtaining an interlocutory quia timet order to impound assets of a defendant without a trial?

In Aetna Financial Services v. Feigelman, 1985 CanLII 55 (SCC), [1985] 1 S.C.R. 2, had occasion to express the reasons behind these tests. The unanimous judgment of the court found, at p. 10: A second and much higher hurdle facing the litigant seeking the exceptional order is the simple proposition that in our jurisprudence, execution cannot be obtained prior to judgment and judgment cannot be recovered before trial. Execution in this sense includes judicial orders impounding assets or otherwise restricting the rights of the defendant without a trial. And, again at p. 37: There is still, as in the days of Lister, a profound unfairness in a rule which sees one’s assets tied up indefinitely pending trial of an action which may not succeed, and even if it does succeed, which may result in an award of far less than the caged assets. The harshness of such an exception to the general rule is even less acceptable where the defendant is a resident within the jurisdiction of the court and the assets in question are not being disposed of or moved out of the country or put beyond the reach of the courts of the country. This sub-rule or exception can lead to serious abuse. A plaintiff with an apparent claim, without ultimate substance, may, by the Mareva exception to the Lister rule, tie up the assets of the defendant, not for the purpose of their preservation until judgment, but to force, by litigious blackmail, a settlement on the defendant who, for any one of many reasons, cannot afford to await the ultimate vindication after trial. I would, with all respect to those who have held otherwise, conclude that the order would not have been issued under the principles of interlocutory quia timet orders in Canadian courts functioning as they do in a federal system.