What is the legal test for "heat of passion" manslaughter?

"'Murder is the unlawful killing of a human being . . . with malice aforethought.' (Pen. Code, 187, subd. (a).) When an unlawful killing occurs 'upon a sudden quarrel or heat of passion' (Pen. Code, 192, subd. (a)) the killer lacks malice, and the crime is voluntary manslaughter, a lesser offense necessarily included within the crime of murder. [Citation.]" (People v. Dungo, supra, 55 Cal.4th at p. 615, fn. 4.) The heat of passion form of voluntary manslaughter is distinguished from murder by provocation. (People v. Souza (2012) 54 Cal.4th 90, 116.) "'The "'heat of passion must be such a passion as would naturally be aroused in the mind of an ordinarily reasonable person under the given facts and circumstances. . . .'" [Citation.]' (Ibid.)" (Ibid.)