What is the test for predatory pricing under s. 36 of the Competition Act?

In Culhane v. ATP Aero Training Products Inc., [2004] F.C.J. No. 669, 2004 FC 535, the claim was pursuant to s. 36 of the Competition Act for “predatory pricing” contrary to s. 50 of the Act. At trial, O’Keefe, J. said in para. 37. 37 The plaintiff has presented evidence to show that his sales of his competing exam guides have decreased in the relevant time period but that is not the relevant issue under this factor. The issue is whether the defendants’ unreasonably low price of their exam guides actually caused the loss or drop in sales to the plaintiff. ... He then referred to evidence at trial and concluded in that para.: This evidence suggests various causal factors at play that could explain the fluctuations in the plaintiff’s sales, aside from the defendants’ conduct. He concluded he was not satisfied there had been a breach of s. 50. On appeal, his decision was upheld. ([2005] F.C.J. No. 591, 2005 FCA 129)