test(lib): promote pollWithTimeout/awaitWithTimeout helpers (#27626)

packages/opencode/test/AGENTS.md

@@ -157,3 +157,47 @@ const failingAccountLayer = Layer.mock(Account.Service, {
 ```
 
 This is much shorter than stubbing every method with `Effect.void` / `Effect.succeed(...)` placeholders, and it keeps the test focused on the behaviour under test.
+
+## Synchronizing With Concurrent Work
+
+### The Anti-Pattern
+
+Using `Effect.sleep(N)` or `setTimeout` as a "wait for the forked fiber to be ready" hack races the scheduler. The forked fiber may not have reached the synchronization point within `N` ms on a slow CI host, and the test fails intermittently. See PR #27622 for a concrete flake that fell out of this exact pattern.
+
+### The Fix
+
+Wait on a **published readiness signal**, not wall-clock time. Available affordances:
+
+- `pollWithTimeout(effect, message, duration?)` from `test/lib/effect.ts` — repeatedly run a predicate effect until it returns a non-`undefined` value, with a timeout.
+- `awaitWithTimeout(effect, message, duration?)` from `test/lib/effect.ts` — wrap any effect with `Effect.timeoutOrElse` and a custom error message.
+- `llm.wait(n)` from `test/lib/llm-server.ts` — wait until the mock LLM has received `n` HTTP calls.
+- `SessionStatus.Service` `.get(sessionID)` — observable per-session state (`{ type: "busy" | "idle" | ... }`).
+- `BackgroundJob.wait({ id, timeout })` from `src/background/job.ts` — wait for a background job to complete.
+- Bus subscriptions — fork `Stream.runForEach(bus.subscribe(Event), ...)` and open a `Latch` inside the callback to signal first-event readiness.
+- `Deferred.await(deferred).pipe(Effect.timeoutOrElse(...))` for one-shot signals.
+
+### Example
+
+```ts
+// Antipattern — race
+yield* prompt.shell({ command: "sleep 30" }).pipe(Effect.forkChild)
+yield* Effect.sleep(50)
+yield* prompt.cancel(chat.id)
+
+// Fix — wait for a published readiness signal
+yield* prompt.shell({ command: "sleep 30" }).pipe(Effect.forkChild)
+yield* pollWithTimeout(
+  Effect.gen(function* () {
+    const s = yield* (yield* SessionStatus.Service).get(chat.id)
+    return s.type === "busy" ? (true as const) : undefined
+  }),
+  "session never became busy",
+)
+yield* prompt.cancel(chat.id)
+```
+
+### When Fixed Sleeps Are OK
+
+- Testing debounce or throttle behavior, where the sleep **is** the test.
+- Letting real wall-clock advance past a genuine timestamp resolution boundary (e.g. mtime granularity).
+- Simulating network latency in race-regression tests that intentionally exercise ordering.

packages/opencode/test/lib/effect.ts

@@ -1,5 +1,5 @@
 import { test, type TestOptions } from "bun:test"
-import { Cause, Effect, Exit, Layer } from "effect"
+import { Cause, Duration, Effect, Exit, Layer } from "effect"
 import type * as Scope from "effect/Scope"
 import * as TestClock from "effect/testing/TestClock"
 import * as TestConsole from "effect/testing/TestConsole"
@@ -109,3 +109,33 @@ export const it = make(testEnv, liveEnv)
 
 export const testEffect = <R, E>(layer: Layer.Layer<R, E>) =>
   make(Layer.provideMerge(layer, testEnv), Layer.provideMerge(layer, liveEnv))
+
+export const awaitWithTimeout = <A, E, R>(
+  self: Effect.Effect<A, E, R>,
+  message: string,
+  duration: Duration.Input = "2 seconds",
+) =>
+  self.pipe(
+    Effect.timeoutOrElse({
+      duration,
+      orElse: () => Effect.fail(new Error(message)),
+    }),
+  )
+
+export const pollWithTimeout = <A, E, R>(
+  self: Effect.Effect<A | undefined, E, R>,
+  message: string,
+  duration: Duration.Input = "5 seconds",
+) =>
+  Effect.gen(function* () {
+    while (true) {
+      const result = yield* self
+      if (result !== undefined) return result
+      yield* Effect.sleep("20 millis")
+    }
+  }).pipe(
+    Effect.timeoutOrElse({
+      duration,
+      orElse: () => Effect.fail(new Error(message)),
+    }),
+  )

packages/opencode/test/mcp/oauth-browser.test.ts

@@ -1,8 +1,7 @@
 import { expect, mock, beforeEach } from "bun:test"
 import { EventEmitter } from "events"
 import { Deferred, Effect, Layer, Option } from "effect"
-import type { Duration } from "effect"
-import { testEffect } from "../lib/effect"
+import { awaitWithTimeout, testEffect } from "../lib/effect"
 import type { MCP as MCPNS } from "../../src/mcp/index"
 
 // Track open() calls and control failure behavior
@@ -135,18 +134,6 @@ const config = (name: string) => ({
 
 const withCallbackStop = Effect.addFinalizer(() => Effect.promise(() => McpOAuthCallback.stop()).pipe(Effect.ignore))
 
-const awaitWithTimeout = <A, E, R>(
-  self: Effect.Effect<A, E, R>,
-  message: string,
-  duration: Duration.Input = "5 seconds",
-) =>
-  self.pipe(
-    Effect.timeoutOrElse({
-      duration,
-      orElse: () => Effect.fail(new Error(message)),
-    }),
-  )
-
 const trackBrowserOpen = Effect.gen(function* () {
   const opened = yield* Deferred.make<string>()
   openDeferred = opened
@@ -184,7 +171,11 @@ mcpTest.instance(
       const event = yield* trackBrowserOpenFailed
       yield* authenticateScoped("test-oauth-server")
 
-      const failure = yield* awaitWithTimeout(Deferred.await(event), "Timed out waiting for BrowserOpenFailed event")
+      const failure = yield* awaitWithTimeout(
+        Deferred.await(event),
+        "Timed out waiting for BrowserOpenFailed event",
+        "5 seconds",
+      )
 
       expect(failure.mcpName).toBe("test-oauth-server")
       expect(failure.url).toContain("https://")
@@ -203,7 +194,7 @@ mcpTest.instance(
       const event = yield* trackBrowserOpenFailed
       yield* authenticateScoped("test-oauth-server-2")
 
-      yield* awaitWithTimeout(Deferred.await(opened), "Timed out waiting for open()")
+      yield* awaitWithTimeout(Deferred.await(opened), "Timed out waiting for open()", "5 seconds")
       const failure = yield* Deferred.await(event).pipe(Effect.timeoutOption("700 millis"))
 
       expect(failure).toEqual(Option.none())
@@ -224,7 +215,7 @@ mcpTest.instance(
       const event = yield* trackBrowserOpenFailed
       yield* authenticateScoped("test-oauth-server-3")
 
-      const url = yield* awaitWithTimeout(Deferred.await(opened), "Timed out waiting for open()")
+      const url = yield* awaitWithTimeout(Deferred.await(opened), "Timed out waiting for open()", "5 seconds")
       const failure = yield* Deferred.await(event).pipe(Effect.timeoutOption("700 millis"))
 
       expect(failure).toEqual(Option.none())

packages/opencode/test/session/prompt.test.ts

@@ -49,7 +49,7 @@ import { Ripgrep } from "../../src/file/ripgrep"
 import { Format } from "../../src/format"
 import { Reference } from "../../src/reference/reference"
 import { TestInstance } from "../fixture/fixture"
-import { testEffect } from "../lib/effect"
+import { awaitWithTimeout, pollWithTimeout, testEffect } from "../lib/effect"
 import { reply, TestLLMServer } from "../lib/llm-server"
 import { SyncEvent } from "@/sync"
 import { RuntimeFlags } from "@/effect/runtime-flags"
@@ -306,36 +306,6 @@ const useServerConfig = Effect.fn("test.useServerConfig")(function* (config: (ur
   return { dir, llm }
 })
 
-const awaitWithTimeout = <A, E, R>(
-  self: Effect.Effect<A, E, R>,
-  message: string,
-  duration: Duration.Input = "2 seconds",
-) =>
-  self.pipe(
-    Effect.timeoutOrElse({
-      duration,
-      orElse: () => Effect.fail(new Error(message)),
-    }),
-  )
-
-const pollWithTimeout = <A, E, R>(
-  self: Effect.Effect<A | undefined, E, R>,
-  message: string,
-  duration: Duration.Input = "5 seconds",
-) =>
-  Effect.gen(function* () {
-    while (true) {
-      const result = yield* self
-      if (result !== undefined) return result
-      yield* Effect.sleep("20 millis")
-    }
-  }).pipe(
-    Effect.timeoutOrElse({
-      duration,
-      orElse: () => Effect.fail(new Error(message)),
-    }),
-  )
-
 // Wait for a session's runner to enter a busy state. SessionStatus is flipped to
 // "busy" inside Runner.startShell's modifyEffect at the same moment the runner
 // is registered, so this is a deterministic readiness signal — cancel can't