diigo-cache: the caches take their clock as a constructor argument

Ocap discipline: no ambient time in logic. PagedCache reads time and
waits only through a Clock { now, sleep }, a default constructor
argument (the live clock; the runtime constructs DOs with ctx and env
only). The fill job's timestamps and alarms, the etch time, and the
diigo-call pacing all go through it.

Tests interpose through the constructor: tests/test-worker.ts (now the
tests' main module) adds FixedClockCache, bound as CLOCKED_DO, and a
test pins startedAt, updatedAt, and the alarm time to the fixed clock
(an ambient new Date() fails it).

Generated-by: Claude Opus 5.5

diigo-cache/src/cache.ts

@@ -84,9 +84,19 @@ function disposeStub(stub: unknown): void {
 	if (typeof dispose === "function") dispose.call(stub);
 }
 
-function sleep(ms: number): Promise<void> {
-	return new Promise((r) => setTimeout(r, ms));
-}
+/** the clock authority a cache uses: reading time, and waiting. Passed
+ * in (ocap discipline), so tests can interpose a fixed clock. */
+export type Clock = {
+	/** epoch milliseconds */
+	now(): number;
+	sleep(ms: number): Promise<void>;
+};
+
+/** the live clock: the one place this module touches time */
+const liveClock: Clock = {
+	now: () => Date.now(),
+	sleep: (ms) => new Promise((r) => setTimeout(r, ms)),
+};
 
 /** a cache's wiring: the webapp instance it asks on a miss, plus (private
  * cache only) the public companion's id, recorded once published */
@@ -110,6 +120,19 @@ export type CacheEnv = {
 abstract class PagedCache extends DurableObject<CacheEnv> {
 	#step = 0;
 	#pause?: Promise<void>;
+	#clock: Clock;
+
+	/** the runtime constructs DOs with (ctx, env); `clock` defaults to the
+	 * live one, and a subclass can pass another */
+	constructor(ctx: DurableObjectState, env: CacheEnv, clock: Clock = liveClock) {
+		super(ctx, env);
+		this.#clock = clock;
+	}
+
+	/** now, as an ISO timestamp */
+	#iso(): string {
+		return new Date(this.#clock.now()).toISOString();
+	}
 
 	/** one-shot wiring. Idempotent; different values are refused (mint a
 	 * new cache instead). */
@@ -146,7 +169,7 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 		if (current?.state === "running") return current;
 		const step = Math.trunc(opts.pagesPerStep ?? 20);
 		if (!(step >= 1 && step <= 50)) throw new Error("pagesPerStep: expected 1–50");
-		const now = new Date().toISOString();
+		const now = this.#iso();
 		const status: FillStatus = {
 			state: "running",
 			nextPage: 1,
@@ -156,7 +179,7 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 			updatedAt: now,
 		};
 		await this.ctx.storage.put({ fill: status, fillStep: step });
-		await this.ctx.storage.setAlarm(Date.now() + FILL_STEP_DELAY_MS);
+		await this.ctx.storage.setAlarm(this.#clock.now() + FILL_STEP_DELAY_MS);
 		console.log({ event: "fill", kind: this.kind, state: status.state, pagesPerStep: step });
 		return status;
 	}
@@ -173,7 +196,7 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 		const current = await this.fillStatus();
 		if (!current) throw new Error("no fill job to stop");
 		if (current.state !== "running") return current;
-		const stopped: FillStatus = { ...current, state: "stopped", updatedAt: new Date().toISOString() };
+		const stopped: FillStatus = { ...current, state: "stopped", updatedAt: this.#iso() };
 		await this.ctx.storage.put("fill", stopped);
 		await this.ctx.storage.deleteAlarm();
 		console.log({ event: "fill", kind: this.kind, state: "stopped", nextPage: stopped.nextPage, pages: stopped.pages });
@@ -197,10 +220,10 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 					nextPage: status.nextPage + 1,
 					pages: Math.max(1, Math.ceil(page.total / PAGE_SIZE)),
 					fetched: status.fetched + (page.cached ? 0 : 1),
-					updatedAt: new Date().toISOString(),
+					updatedAt: this.#iso(),
 				};
 			} catch (err) {
-				status = { ...status, state: "failed", error: String(err), updatedAt: new Date().toISOString() };
+				status = { ...status, state: "failed", error: String(err), updatedAt: this.#iso() };
 				console.error({ event: "fill", kind: this.kind, state: "failed", page: status.nextPage, error: status.error });
 			}
 			// a stop that landed mid-step wins
@@ -209,11 +232,11 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 		}
 		if (!status) return;
 		if (status.state === "running" && status.pages !== null && status.nextPage > status.pages) {
-			status = { ...status, state: "done", updatedAt: new Date().toISOString() };
+			status = { ...status, state: "done", updatedAt: this.#iso() };
 		}
 		await this.ctx.storage.put("fill", status);
 		console.log({ event: "fill", kind: this.kind, state: status.state, nextPage: status.nextPage, pages: status.pages, fetched: status.fetched });
-		if (status.state === "running") await this.ctx.storage.setAlarm(Date.now() + FILL_STEP_DELAY_MS);
+		if (status.state === "running") await this.ctx.storage.setAlarm(this.#clock.now() + FILL_STEP_DELAY_MS);
 	}
 
 	/** diigo's page count, if any cached page recorded `total` */
@@ -244,7 +267,7 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 			if (this.#pause) await this.#pause;
 		} while (before !== this.#step);
 		this.#step += 1;
-		this.#pause = sleep(MS_PER_CALL);
+		this.#pause = this.#clock.sleep(MS_PER_CALL);
 
 		const hit = await this.#pageFromStorage(pageNum, count);
 		if (hit) {
@@ -288,7 +311,7 @@ abstract class PagedCache extends DurableObject<CacheEnv> {
 			}
 			this.ctx.storage.sql.exec(
 				"insert into pages (page_num, count, total, etched_at) values (?, ?, ?, ?) on conflict(page_num) do update set count = excluded.count, total = excluded.total, etched_at = excluded.etched_at",
-				pageNum, count, total, new Date().toISOString(),
+				pageNum, count, total, this.#iso(),
 			);
 		});
 		return { total, items: rows.map((r) => r.json), cached: false };

diigo-cache/tests/fill.test.ts

@@ -5,6 +5,7 @@ import worker from "../src/index.js";
 import { newHttpBatchRpcSession } from "capnweb";
 import type { CacheApi } from "../src/api.js";
 import { toWebkey } from "../src/webkeys.js";
+import { FIXED_NOW } from "./test-worker.js";
 
 // goal 1e (capsite checklist): a job that grabs every page. Fake
 // accounts: tests/fake-webapp.js ("fake-webapp-id": 30 items = 2 pages
@@ -12,6 +13,7 @@ import { toWebkey } from "../src/webkeys.js";
 
 type TestEnv = {
 	CACHE_DO: DurableObjectNamespace<import("../src/cache.js").DiigoCache>;
+	CLOCKED_DO: DurableObjectNamespace<import("./test-worker.js").FixedClockCache>;
 	PUBLIC_DO: DurableObjectNamespace<import("../src/cache.js").PublicCache>;
 	WEBAPP: { calls(): Promise<number> };
 };
@@ -107,6 +109,18 @@ describe("fill job (goal 1e)", () => {
 		}
 	});
 
+	it("reads time only through its clock: a fixed clock pins the timestamps and the alarm", async () => {
+		const stub = testEnv.CLOCKED_DO.get(testEnv.CLOCKED_DO.newUniqueId());
+		await stub.setup({ webappId: "fake-webapp-id" });
+		const at = new Date(FIXED_NOW).toISOString();
+		expect(await stub.startFill()).toMatchObject({ startedAt: at, updatedAt: at });
+		await runInDurableObject(stub, async (_obj, state) => {
+			expect(await state.storage.getAlarm()).toBe(FIXED_NOW + 1000);
+		});
+		await drain(stub);
+		expect(await stub.fillStatus()).toMatchObject({ state: "done", updatedAt: at });
+	});
+
 	it("a public cache's fill stores no private rows", async () => {
 		const stub = testEnv.PUBLIC_DO.get(testEnv.PUBLIC_DO.newUniqueId());
 		await stub.setup({ webappId: "fake-webapp-id" });

diigo-cache/tests/test-worker.ts

@@ -0,0 +1,19 @@
+/**
+ * @file the tests' main module: the real worker, plus a DiigoCache on a
+ * fixed clock (bound as CLOCKED_DO in wrangler.tests.jsonc), so tests can
+ * interpose time through the constructor.
+ */
+import { DiigoCache } from "../src/cache.js";
+import type { CacheEnv } from "../src/cache.js";
+
+export * from "../src/index.js";
+export { default } from "../src/index.js";
+
+/** 2026-10-07T12:00:00Z */
+export const FIXED_NOW = Date.UTC(2026, 9, 7, 12, 0, 0);
+
+export class FixedClockCache extends DiigoCache {
+	constructor(ctx: DurableObjectState, env: CacheEnv) {
+		super(ctx, env, { now: () => FIXED_NOW, sleep: async () => {} });
+	}
+}

diigo-cache/wrangler.tests.jsonc

@@ -1,9 +1,10 @@
 {
 	"$schema": "node_modules/wrangler/config-schema.json",
-	// the real worker, with WEBAPP bound to tests/fake-webapp.js (an aux
-	// worker declared in vitest.config.ts)
+	// the real worker (via tests/test-worker.ts, which adds a fixed-clock
+	// cache), with WEBAPP bound to tests/fake-webapp.js (an aux worker
+	// declared in vitest.config.ts)
 	"name": "diigo-cache-tests",
-	"main": "./src/index.ts",
+	"main": "./tests/test-worker.ts",
 	"compatibility_date": "2026-09-29",
 	"rules": [{ "type": "Text", "globs": ["**/capnweb/dist/index.js"], "fallthrough": true }],
 	"services": [
@@ -12,11 +13,13 @@
 	"durable_objects": {
 		"bindings": [
 			{ "name": "CACHE_DO", "class_name": "DiigoCache" },
-			{ "name": "PUBLIC_DO", "class_name": "PublicCache" }
+			{ "name": "PUBLIC_DO", "class_name": "PublicCache" },
+			{ "name": "CLOCKED_DO", "class_name": "FixedClockCache" }
 		]
 	},
 	"exports": {
 		"DiigoCache": { "type": "durable-object", "storage": "sqlite" },
-		"PublicCache": { "type": "durable-object", "storage": "sqlite" }
+		"PublicCache": { "type": "durable-object", "storage": "sqlite" },
+		"FixedClockCache": { "type": "durable-object", "storage": "sqlite" }
 	}
 }