diigo-cache: test that a cached page replays fetch-time order

A hit must replay diigo's order as fetched (page_members.pos), not a
column sort. The fake webapp's link_id and updated_at are scrambled so
neither column sorts back into diigo's order; ordering the replay by
updated or item_id fails the new test.

Generated-by: Claude Opus 5.5

diigo-cache/tests/caches.test.ts

@@ -79,6 +79,23 @@ describe("DiigoCache", () => {
 	});
 });
 
+describe("page replay order", () => {
+	it("a hit replays diigo's fetch-time order (page_members), not a column sort", async () => {
+		const stub = testEnv.CACHE_DO.get(testEnv.CACHE_DO.newUniqueId());
+		await stub.setup({ webappId: WEBAPP_ID });
+		const titles = (items: string[]) => parse(items).map((i) => i.title);
+		const expected = Array.from({ length: 24 }, (_, k) => `bookmark ${k + 1}`);
+
+		const miss = await stub.page(1, 24);
+		expect(titles(miss.items)).toEqual(expected);
+		// page 2's etch upserts other rows; page 1's replay must not shift
+		await stub.page(2, 24);
+		const hit = await stub.page(1, 24);
+		expect(hit.cached).toBe(true);
+		expect(titles(hit.items)).toEqual(expected);
+	});
+});
+
 describe("worker routes", () => {
 	const call = (path: string, init?: RequestInit) =>
 		worker.fetch(new Request(`https://diigo-cache.test${path}`, init), env as never);

diigo-cache/tests/fake-webapp.js

@@ -10,10 +10,13 @@ import { RpcTarget, WorkerEntrypoint } from "cloudflare:workers";
 const KNOWN_WEBAPP = "fake-webapp-id";
 const TOTAL = 30;
 
-/** item n (1-based, updated-desc order): diigo's field names, made-up values */
+/** item n (1-based, in diigo's order): diigo's field names, made-up
+ * values. link_id and updated_at are scrambled (distinct; 7 and 11 are
+ * coprime to 31), so neither column sorts back into diigo's order — a
+ * cache that replays by column rather than by fetch order is caught. */
 function item(n) {
 	return {
-		link_id: 1000 + n,
+		link_id: 1000 + ((n * 7) % 31),
 		url: `https://example.com/${n}`,
 		title: `bookmark ${n}`,
 		description: "",
@@ -23,7 +26,7 @@ function item(n) {
 		user_id: 4242,
 		tags: "",
 		created_at: 1700000000,
-		updated_at: 1700001000 - n,
+		updated_at: 1700001000 + ((n * 11) % 31),
 	};
 }