What is the test for establishing that a husband and wife signed an agreement that the wife would not interfere with the disbursement and distribution of her earnings?

The facts in Kaltschmidt v. Weber, 145 Cal. 596, 79 P. 272, are remarkably comparable to the instant case, although the litigation was of a probate nature. The wife had kept a boarding house for many years, during which time she collected all the rents and managed the disbursement of all funds without interference or objection of her husband. Said the court, 145 Cal. at pages 599-600, 79 P. at page 274: 'Now, it may well have been the case that the husband could recall no conversation between them in which such an agreement was distinctly expressed. His testimony strongly indicates this condition of memory. And yet it might also be true that the fact that there was such an agreement was perfectly well understood between them. In such a case resort may be had to circumstantial evidence. The conduct and actions of the husband with respect to such earnings, indicating that he did not regard them as community property, or that he had relinquished to her the right to control and dispose of her receipts from that source, would be competent evidence and admissible to prove [129 Cal.App.2d 157] the agreement. * * * If, in connection with all these facts, the plaintiff had been allowed to prove that during the 22 years of their married life the wife had had exclusive and undisturbed control of her earnings, treating the same as her own property, and disposing of them as she pleased, without consulting her husband, such evidence would certainly tend to prove an understanding between them that such earnings were to be her own separate estate.'