What is the test for severance in real estate law?

Justice Coady goes on to say at page 5: However it is largely then a matter of what inference can reasonably be drawn from the evidence and while the agreement itself does not operate as a severance there may be conduct and acts of the parties from which severance can be inferred. In Crooke v. De Vandes (1805), 11 Ves. 330, 32 E.R. 115, the headnote reads as follows” “An agreement for severance as to the whole may be inferred from their conduct; dividing, as the property was received.”