diff --git a/examples/toaster/test/migration.ts b/examples/toaster/test/migration.ts
index 953e8a0..992f9b8 100644
--- a/examples/toaster/test/migration.ts
+++ b/examples/toaster/test/migration.ts
@@ -12,7 +12,6 @@ import {
   awaitMigrated,
   waitForWorkflowCondition,
 } from '@diachronic/migrate/test'
-import { sleep } from '@diachronic/util/sleep'
 
 jest.setTimeout(120_000)
 beforeAll(async () => {
diff --git a/examples/toaster/test/nondeterminism.ts b/examples/toaster/test/nondeterminism.ts
new file mode 100644
index 0000000..f901059
--- /dev/null
+++ b/examples/toaster/test/nondeterminism.ts
@@ -0,0 +1,88 @@
+import {
+  DefaultLogger,
+  Runtime,
+  Worker,
+  WorkerOptions,
+} from '@temporalio/worker'
+import { DeterminismViolationError } from '@temporalio/workflow'
+import { TestWorkflowEnvironment } from '@temporalio/testing'
+import { Trigger } from '@diachronic/util/trigger'
+import { getTimeLeft } from '@diachronic/migrate/interpreter'
+import { waitForWorkflowCondition } from '@diachronic/migrate/test'
+
+jest.setTimeout(120_000)
+beforeAll(async () => {
+  Runtime.install({
+    logger: new DefaultLogger('WARN'),
+  })
+})
+test('toaster nondeterminism', async () => {
+  const testEnv = await TestWorkflowEnvironment.createLocal()
+  const prevWorkflowConfig: WorkerOptions = {
+    connection: testEnv.nativeConnection,
+    taskQueue: 'initial',
+    workflowsPath: require.resolve('./../src/index'),
+  }
+
+  const prevWorker = await Worker.create(prevWorkflowConfig)
+  const prevWorkflowRun = await testEnv.client.workflow.signalWithStart(
+    'toaster',
+    {
+      taskQueue: prevWorkflowConfig.taskQueue,
+      workflowId: '42',
+      signal: 'plug-it-in',
+      signalArgs: [undefined],
+      followRuns: true,
+      retry: {
+        maximumAttempts: 1,
+      },
+    }
+  )
+  const prevWorkerTrigger = new Trigger()
+  // @ts-expect-error
+  const prevWorkerRun = prevWorker.runUntil(prevWorkerTrigger)
+
+  await waitForWorkflowCondition(
+    prevWorkflowRun,
+    (snapshot) => snapshot.state === 'OFF'
+  )
+  const timerDuration = 5000
+  await prevWorkflowRun.signal('set-toast-time', {
+    duration: timerDuration,
+  })
+  const state = await waitForWorkflowCondition(
+    prevWorkflowRun,
+    (snapshot) => snapshot.state === 'ON'
+  )
+
+  const timers = Object.values(state.timers)
+  expect(timers.length).toEqual(1)
+  expect(timers[0].delay).toEqual(timerDuration)
+
+  const timeLeft = getTimeLeft(timers[0], await testEnv.currentTimeMs())
+
+  expect(timeLeft).toBeGreaterThan(0)
+  expect(timeLeft).toBeLessThan(timerDuration)
+
+  prevWorkerTrigger.resolve()
+
+  // roll out new code
+  const nextWorkflowWorkerConfig: WorkerOptions = {
+    connection: testEnv.nativeConnection,
+    taskQueue: prevWorkflowConfig.taskQueue,
+    workflowsPath: require.resolve('./../src/v2'),
+  }
+  const history = await prevWorkflowRun.fetchHistory()
+  try {
+    await Worker.runReplayHistory(nextWorkflowWorkerConfig, history)
+      .then(() => {
+        throw new Error('Expected Worker.runReplayHistory to throw')
+      })
+      .catch((err) => {
+        expect(err instanceof DeterminismViolationError).toEqual(true)
+      })
+  } finally {
+    await Promise.all([prevWorkerRun])
+    await testEnv!.teardown()
+  }
+})