interval-timer-testing.md

Interval timer (testing) — PrimeTime (NodaTime) stack

These xUnit examples drive interval timers under a virtual PrimeTestClock. Callbacks fire only when the test advances the clock, so the assertions are deterministic and there are no real-world wait times.

[!code-csharp]

What to notice

• PrimeTestClock is constructed from a NodaTime Instant so the NodaTime stack starts at a known UTC instant without timezone ambiguity.
• Advance(Duration) moves virtual time forward; callbacks scheduled at or before the new "now" are dispatched synchronously by the test clock before Advance returns.
• A one-shot timer is requested by passing Timeout.InfiniteTimeSpan as the repeat interval. IClockIntervalTimer.IsRepeating is false for one-shot registrations.
• For repeating timers, advancing past each multiple of the repeat interval produces one callback per interval crossed.
• The async overload (RegisterAsyncTimer) completes the awaited callback before Advance returns.

Related

• Interval timer (production) — wall-clock counterpart in the example app.
• Test-clock control APIs — Set*, Advance, RunFor, Start/Stop, marching, and automatic runner semantics for both stacks.
• API: IPrimeTestClock · PrimeTestClock