What it means
Testamentary capacity is the mental ability a person must have when making a will. The classic test (from Banks v Goodfellow) requires the will-maker to understand that they are making a will and its effect, know the general nature and extent of their property, and appreciate who might reasonably expect to benefit, without any disorder of mind distorting their judgment. Capacity is assessed at the time the will is made. Concerns about dementia or illness can lead to a will being challenged across all Australian jurisdictions.
How it's used
The doctor provided a report confirming her testamentary capacity before she signed the will, reducing the risk of a later challenge.