What is the legal test for a valid will?

For an individual to properly dispose of her estate by way of a valid will, she must have testamentary capacity, that is, as stated by the court in Banks v. Goodfellow, she must understand that she is indeed making a will that will have the effect of disposing of her assets. She must also understand the extent of her assets. As stated by Veit, J in Dansereau Estate v. Vallee, [1999] AJ 878, at para. 157: A testator must have general knowledge of their property. The legal standard is usefully summarized by Hull: While there is much jurisprudence about what is and what is not testamentary capacity, they can generally be rolled up in my own definition: to know and understand that one is executing a testmentary document disposing of assets, the general value and nature of which are known to the testator or testatrix, after having considered all persons having a moral claim to the assets being disposed of. [emphasis added]