diff --git a/src/services/wiki/plugin/watchFileSystemAdaptor/__tests__/FileSystemAdaptor.routing.test.ts b/src/services/wiki/plugin/watchFileSystemAdaptor/__tests__/FileSystemAdaptor.routing.test.ts
index cbe49df0..0654e8ca 100644
--- a/src/services/wiki/plugin/watchFileSystemAdaptor/__tests__/FileSystemAdaptor.routing.test.ts
+++ b/src/services/wiki/plugin/watchFileSystemAdaptor/__tests__/FileSystemAdaptor.routing.test.ts
@@ -39,7 +39,7 @@ global.$tw = {
   utils: mockUtils,
   wiki: {
     filterTiddlers: vi.fn(() => []),
-    makeTiddlerIterator: vi.fn((titles) => titles),
+    makeTiddlerIterator: vi.fn((titles: string[]) => titles),
   },
   rootWidget: {
     makeFakeWidgetWithVariables: vi.fn(() => ({})),