Definition
Plain language
A small automated check that a single piece of code — or, here, a single definition — behaves the way it's supposed to.
As stated in the literature
A test asserting a property that should hold if a component is correct; in autoformalization, auxiliary lemmas serve as unit tests for a new formal definition, since a definition's meaning can't be checked by the compiler directly.
Also called: unit tests
Why it matters: It matters because these small checks catch broken behavior early, and can even verify a formal definition means what its author intended.
For example, a test might feed a sorting function an unsorted list and check that it comes back in order.
Heard on the show
“A typical code version is: generate code, run unit tests, retry with the error message if tests fail.”Episode 013 — Why Search Keeps Rediscovering the Same Workflow, and What That Means