What are the legal tests for determining whether a third party has a duty to exercise ordinary care not to injure another person?

As stated in Connor, supra, at pages 865, 73 Cal.Rptr. at p. 377, 447 P.2d at p. 617: "Privity of contract is not necessary to establish the existence of a duty to exercise ordinary care not to injure another, but such duty may arise out of a voluntarily assumed relationship if public policy dictates the existence of such a duty.' (Citations.) The basic tests for determining the existence of such a duty are clearly set forth in Biakanja v. Irving, * * * 49 Cal.2d 647, 650, 320 P.2d 16, 19 (65 A.L.R.2d 1358), as follows: 'The determination whether in a specific case the defendant will be held liable to a third person not in privity is a matter of policy and involves the balancing of various factors among which are (1) the extent to which the transaction was intended to affect the plaintiff, (2) the foreseeability of harm to him, (3) the degree of certainty that the plaintiff suffered injury, (4) the closeness of the connection between the defendant's conduct and the injury suffered, (5) the moral blame attached to the defendant's conduct, and (6) the policy of preventing future harm."