From a1584bc8b37635cdf05ad7a3fe39ef9f7e83f620 Mon Sep 17 00:00:00 2001
From: sneak <sneak@sneak.berlin>
Date: Wed, 14 Oct 2026 00:40:15 +0000
Subject: [PATCH] Test: a backup limited to one album stores a file whose copy
 there does not decrypt

A run of lib.backup() limited to "Trip" must store a file whose copy in
Trip does not decrypt when its copy in an album the run skips does. Today
the run neither stores it nor records it as failed.

Model: opus-5-5
---
 test/cli/backup-undecryptable.test.ts | 37 ++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/test/cli/backup-undecryptable.test.ts b/test/cli/backup-undecryptable.test.ts
index 72adc11..9500dc0 100644
--- a/test/cli/backup-undecryptable.test.ts
+++ b/test/cli/backup-undecryptable.test.ts
@@ -37,8 +37,9 @@ import {
     type CliContext,
 } from "../../src/cli-commands.js";
 import { loadSession } from "../../src/cli-session.js";
-import type { ClientSnapshot } from "../../src/client.js";
+import { Client, type ClientSnapshot } from "../../src/client.js";
 import { encryptBlob, init, toBase64 } from "../../src/crypto/index.js";
+import { Library } from "../../src/library/index.js";
 
 const USER_ID = 42;
 
@@ -412,6 +413,40 @@ describe("quak backup with records it cannot decrypt", () => {
         expect(stored(30)).toBe(true);
         expect(failures()).toEqual({});
     });
+
+    it("backs up that file in a run limited to the album where it does not decrypt", async () => {
+        // The same account, backed up by `lib.backup()` limited to album 1,
+        // "Trip", as `quak backup` cannot be. File 30 is in Trip, so the run
+        // must store it, from its copy in album 3 that the run otherwise
+        // skips.
+        const ente = new FakeEnte();
+        ente.putAlbum(1, "Trip", 1);
+        ente.putFile(1, 30, 1, { corruptKey: true });
+        ente.putAlbum(3, "Favorites", 1);
+        ente.putFile(3, 30, 1);
+        const lib = await Library.open({
+            client: Client.fromJSON(ente.snapshot(), {
+                fetch: ente.fetch,
+                retry: { attempts: 1 },
+            }),
+            downloadDirectory: backupDir(),
+            cacheDirectory: join(root, "cache"),
+            precacheThumbnails: false,
+            precacheOriginals: false,
+        });
+        try {
+            const result = await lib.backup({
+                downloadDirectory: backupDir(),
+                onlyAlbumNames: ["Trip"],
+            });
+            expect(result).toMatchObject({ downloaded: 1, failed: 0 });
+        } finally {
+            await lib.close();
+        }
+
+        expect(stored(30)).toBe(true);
+        expect(failures()).toEqual({});
+    });
 });
 
 describe("the read commands with records quak cannot decrypt", () => {