What is the test for making out a prima facie case in a case of nonsuit?

"'Adopting, as we must, the rules of construction that apply to cases of nonsuit, by indulging every favorable inference fairly deducible and every favorable presumption fairly arising from the evidence, and giving to contestant the benefit of every piece of evidence which tends to sustain his averments, as fully stated in Berger v. Lane, 190 Cal. 443 (213 P. 45), and cases cited, it is clear that he has completely failed to make out a prima facie case. * * * The inferences and presumptions spoken of * * * must fall within the realm of rationality. There is nothing in contestant's case which amounts to more than mere conjecture, surmise, or suspicion. To justify the submission of any question of fact to a court or jury there must be proof of a substantial character that the fact is as alleged.''

'In re Estate of Bryson, 191 Cal. 521 (217 P. 525). (Emphasis included.)