Unit
What it is
Per-function pure tests in Vitest. Isolated, fast, example-based. The traditional unit-test layer — Matter's framework treats these as Vitest assertions, not gates, because they're already a well-developed practice.
When to use it
Pure functions with specific known inputs.
Example gates
Vitest suites in __tests__/ directories. Not directly framework-gate-shaped.
See also
- The pyramid — where this mode sits relative to the others
- Writing a gate — how to scaffold a new gate in this mode
- Decision tree — "I just wrote feature X — what tests do I owe?"