What is the test for determining whether an applicant has a reasonable chance of persecution if they return to their home country of origin?

In Adjei v. Canada (Minister of Employment and Immigration), 1989 CanLII 5184 (FCA), [1989] 2 F.C. 680 (F.C.A.), MacGuigan J.A. indicated: ¶ 5 It was common ground that the objective test is not so stringent as to require a probability of persecution. In other words, although an applicant has to establish his case on a balance of probabilities, he does not nevertheless have to prove that persecution would be more likely than not. [...] ¶ 6 The parties were agreed that one accurate way of describing the requisite test is in terms of "reasonable chance": is there a reasonable chance that persecution would take place were the applicant returned to his country of origin? [...] ¶ 8 What is evidently indicated by phrases such as "good grounds" or "reasonable chance" is, on the one hand, that there need not be more than a 50% chance (i.e., a probability), and on the other hand that there must be more than a minimal possibility. We believe this can also be expressed as a "reasonable" or even a "serious possibility", as opposed to a mere possibility. (my emphasis)