test(quota): add tests for quota-blocked file protection on parent deletion

Two cases:
- quota blocked file survives when its remote parent folder is deleted;
  already synced siblings are still removed.
- regression: a plain new file with no quota error in a server deleted
  folder continues to be deleted as before.

Signed-off-by: Camila Ayres <hello@camilasan.com>

Author: camilasan

test/testsyncdelete.cpp

@@ -52,6 +52,80 @@ private slots:
         QCOMPARE(fakeFolder.currentLocalState(), fakeFolder.currentRemoteState());
     }
 
+    // Verify that a file blocked from uploading by a remote storage quota error is
+    // protected from local deletion when the remote parent folder is subsequently deleted.
+    void testQuotaBlockedFileProtectedFromParentFolderDeletion()
+    {
+        FakeFolder fakeFolder{FileInfo::A12_B12_C12_S12()};
+
+        // Establish an initial clean sync: a1 and a2 exist on both sides.
+        QVERIFY(fakeFolder.syncOnce());
+        QCOMPARE(fakeFolder.currentLocalState(), fakeFolder.currentRemoteState());
+
+        // Add a new local file that will fail to upload due to remote quota (HTTP 507).
+        fakeFolder.localModifier().insert(QStringLiteral("A/quota_blocked.txt"), 100);
+        fakeFolder.serverErrorPaths().append(QStringLiteral("A/quota_blocked.txt"), 507);
+
+        // Sync: upload fails → file is blacklisted as InsufficientRemoteStorage.
+        QVERIFY(!fakeFolder.syncOnce());
+        {
+            auto entry = fakeFolder.syncJournal().errorBlacklistEntry(QStringLiteral("A/quota_blocked.txt"));
+            QVERIFY(entry.isValid());
+            QCOMPARE(entry._errorCategory, SyncJournalErrorBlacklistRecord::InsufficientRemoteStorage);
+        }
+
+        // The file was never uploaded.
+        QVERIFY(!fakeFolder.currentRemoteState().find(QStringLiteral("A/quota_blocked.txt")));
+
+        // Remove the server error so further requests to that path don't return 507.
+        fakeFolder.serverErrorPaths().clear();
+
+        // Server-side: folder A is moved/deleted (e.g., via the web interface).
+        fakeFolder.remoteModifier().remove(QStringLiteral("A"));
+
+        ItemCompletedSpy completeSpy(fakeFolder);
+        fakeFolder.syncOnce();
+
+        // *** Core assertion: quota-blocked file must NOT have been deleted locally. ***
+        QVERIFY(fakeFolder.currentLocalState().find(QStringLiteral("A/quota_blocked.txt")));
+
+        // Parent folder A must also survive because it still contains the protected file.
+        QVERIFY(fakeFolder.currentLocalState().find(QStringLiteral("A")));
+
+        // Previously-synced siblings must have been deleted locally (trust the server).
+        QVERIFY(!fakeFolder.currentLocalState().find(QStringLiteral("A/a1")));
+        QVERIFY(!fakeFolder.currentLocalState().find(QStringLiteral("A/a2")));
+
+        // The quota-blocked file must still not exist on the server.
+        QVERIFY(!fakeFolder.currentRemoteState().find(QStringLiteral("A/quota_blocked.txt")));
+
+        // The protected file must be reported as an error (or blacklisted-error) item, not silently ignored.
+        {
+            auto item = completeSpy.findItem(QStringLiteral("A/quota_blocked.txt"));
+            QVERIFY(item);
+            const bool isErrorItem = item->_instruction == CSYNC_INSTRUCTION_ERROR
+                || item->_instruction == CSYNC_INSTRUCTION_IGNORE; // BlacklistedError reuses IGNORE
+            QVERIFY(isErrorItem);
+            const bool isErrorStatus = item->_status == SyncFileItem::SoftError
+                || item->_status == SyncFileItem::BlacklistedError;
+            QVERIFY(isErrorStatus);
+        }
+    }
+
+    // Regression: non-quota new files in a server-deleted folder must still be deleted locally
+    void testDeleteDirectoryWithNewFileNoQuotaError()
+    {
+        FakeFolder fakeFolder{FileInfo::A12_B12_C12_S12()};
+        fakeFolder.remoteModifier().remove(QStringLiteral("A"));
+        fakeFolder.localModifier().insert(QStringLiteral("A/newfile.txt"), 100);
+
+        QVERIFY(fakeFolder.syncOnce());
+
+        // New local file with no quota blacklist entry must be removed when parent is deleted on server.
+        QVERIFY(!fakeFolder.currentLocalState().find(QStringLiteral("A/newfile.txt")));
+        QCOMPARE(fakeFolder.currentLocalState(), fakeFolder.currentRemoteState());
+    }
+
     void issue1329()
     {
         FakeFolder fakeFolder{ FileInfo::A12_B12_C12_S12() };