Tier 4 — Simulator

A small device with a fast-forwarding clock: multi-day Doze regimes asserted in milliseconds on the JVM.

Multi-day device regimes asserted in milliseconds of JUnit. bridge-sim scripts signal timelines and a fake clock over the real journal, dispatcher, runner, and diagnoser — the production classes, not mocks.

simulate {
    worker("upload") { UploadWorker() }
    bucket(Buckets.RARE)
    doze(fromMs = 1.h, untilMs = 5.h, maintenanceEveryMs = 2.h)
    threadPressure(runnable = 12, fromMs = 2.h)   // MEDIUM on the sim's 8 cores
    val work = enqueue(workRequest("sync", "upload"))
    assertThat(work.verdictAt(3.h).diagnosis).isInstanceOf(Diagnosis.DeferredByDoze::class.java)
    assertThat(work.completedWithin(26.h)).isTrue()
}

Scriptable regime

DSL	Scripts
`bucket(...)`	Standby bucket over time
`doze(...)`	Doze windows with maintenance cadence
`thermal(status)`	PowerManager thermal status level
`threadPressure(runnable)`	Process runnable-thread count (the sim pins 8 cores)
`charging(...)`, `batteryLow(...)`, `storageLow(...)`, `dataSaver(...)`, `bgRestricted(...)`	The remaining constraint gates
`unmetered(...)`, `contentChanged(uri, atMs)`	Network class over time; content-URI trigger firings
`signal(kind, value, fromMs)`	Escape hatch: script any raw signal directly
`restartProcess()`, `advanceTo(ms)`	Simulated process death + relaunch; explicit clock control
`launch(name) { ... }` / `startDurable(...)`	Durable coroutines under the scripted regime

Thirty-one scenario tests across six suites ship with the module — constraint gates, policy escalation, WorkManager-parity chains, timing, and the durable signature test (death at +30 min, deep Doze mid-delay(2h)), including the stall mirror of the device result.

Scope

The simulator’s scope is explicit: a logic assertion under a scripted regime, not a device guarantee. The gating model makes no attempt to reproduce OEM heuristics. Device truth comes from the instrumented suite and the benchmark harness in bench/.