What is the test for the defence of provocation?

In Salamon v. The Queen, 1959 CanLII 5 (SCC), 30 C.R. 1, [1959] S.C.R. 404, 123 C.C.C. 1, 17 D.L.R. (2d) 685, one of the grounds of appeal was that the learned trial Judge erred in his charge to the jury in regard to the defence of provocation. In that case the evidence showed that the appellant had entered the house of the deceased and started the quarrel during which the deceased retaliated. The quarrel subsided due to the intervention of the husband of the deceased, and the deceased went to the washroom. The appellant went to his room and from there proceeded to the washroom. He called her a dirty name causing her to retaliate in similar fashion. He then shot her without anything being said. It was the deceased’s verbal retaliation which the appellant contended was the foundation of the defence of provocation.