Sample

Make tokio timer code deterministic and instant in tests with a paused clock, driving sleep, timeout, interval and select! on virtual time from a hand-built runtime rather than #[tokio::test]

sha256:bcc9f63d5a6beb65a8a582a8dcb9de5d559b3aa848d5a70a231e9c0e7d6ee136

Case

Goal

Make tokio timer code deterministic and instant in tests with a paused clock, driving sleep, timeout, interval and select! on virtual time from a hand-built runtime rather than #[tokio::test] HOW

Packages

tokio 1.53.1

Environment

rust 1

Created

2026-08-14T12:58:22Z

Contract

• assert a one hour sleep under a paused clock advances tokio::time::Instant by exactly one hour
• assert that hour of virtual time costs under 250 milliseconds of real time
• assert timeout on a future that never completes returns Err(Elapsed) whose Display is "deadline has elapsed"
• assert the clock stops exactly on the timeout deadline rather than somewhere past it
• assert a fresh Interval already has one tick due before anything awaits it
• assert taking that first tick costs zero virtual time
• assert advance() past five periods makes five ticks due at once under the default MissedTickBehavior::Burst
• assert the clock sits exactly 300 virtual seconds on from the interval's creation after that advance
• assert four ticks of a 60 second interval take 180 seconds of virtual time, not 240
• assert select! with a timeout branch picks the timeout when the other branch can never resolve
• assert the clock lands exactly on that select! timeout deadline
• assert two select! branches one millisecond apart resolve to the shorter one 100 times in a row
• assert those 100 races cost exactly one second of virtual time in total
• assert the whole run adds up to exactly 4116 seconds of virtual time
• assert 4116 seconds of virtual time pass in under a second of real time
• assert start_paused without enable_time still builds, then panics on the first sleep with the message naming enable_time
• assert a Sleep constructed outside the runtime instead panics that no reactor is running, even when that runtime has its time driver enabled
• assert start_paused on a multi_thread runtime panics inside build() with the message naming the current_thread runtime, instead of returning Err

Files

• Cargo.lock
• Cargo.toml
• csx.json
• src/main.rs

Origin Seeder

anonymous

Verification receipts

• rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-14 · ed25519:a2ec939a4c60e243
• · CONTAINER_RUN · compile:SKIPPED · contract:FAIL · load:SKIPPED · resolve:PASS · cargo@1 · 2026-08-14 · ed25519:7da3f610facce8bf