Module testing 

Testing utilities for nexus-rt handlers and timer drivers.

Two tiers of testing infrastructure:

• TestHarness — dispatch events through handlers directly, auto-advancing sequence numbers, with world access for assertions.
• TestTimerDriver (requires timer feature) — wraps TimerPoller with virtual time control for deterministic timer testing.

Always available (no feature gate).

Structs

TestHarness

Minimal test harness for handler dispatch.

TestTimerDriver

Virtual-time wrapper around TimerPoller for deterministic timer testing.