Function test_uuid 

pub fn test_uuid() -> UUID4

Returns the next [UUID4] in a per-thread deterministic sequence seeded with a fixed value.

The official test runner is cargo nextest, which spawns one process per test, so the sequence resets at every test boundary without explicit teardown. Multiple events constructed within a single test get distinct UUIDs, and re-running the same test produces the same sequence.

Intended for use as a default in test specs and fixtures only.