What is the legal test for making comments in an opening statement?

While the purpose of opening and closing submissions differ, the following observations in Brophy v. Hutchinson, 2003 BCCA 21, 9 B.C.L.R. (4th) 46, at para. 41, are, “for the most part, equally applicable to comments made in closing address” (Lawson v. McGill, 2004 BCCA 68, 23 B.C.L.R. (4th) 254.): In an opening statement, counsel may not give his own personal opinion of the case. Before any evidence is given he may not mention facts which require proof, which cannot be proven by evidence from his own witnesses, or which he expects to elicit only on cross-examination. He may not mention matters that are irrelevant to the case. He must not make prejudicial remarks tending to arouse hostility, or statements that appeal to the jurors' emotions, rather than their reason. It is improper to comment directly on the credibility of witnesses. The opening is not argument, so the use of rhetoric, sarcasm, derision and the like is impermissible …. [Citations omitted.]