fix: improve async-mutex mocking and reset instancePromise on cache close

Author: Ayyanaruto

core/autocomplete/util/AutocompleteLruCache.test.ts

@@ -1,7 +1,11 @@
 import AutocompleteLruCache from "./AutocompleteLruCache";
 
-// Mock the external dependencies before importing
-jest.mock("async-mutex");
+jest.mock("async-mutex", () => {
+  const acquire = jest.fn().mockResolvedValue(jest.fn());
+  return {
+    Mutex: jest.fn().mockImplementation(() => ({ acquire })),
+  };
+});
 jest.mock("sqlite");
 jest.mock("sqlite3");
 

core/autocomplete/util/AutocompleteLruCache.ts

@@ -221,7 +221,7 @@ export class AutocompleteLruCache {
     }
     await this.flush();
     await this.db.close();
+    AutocompleteLruCache.instancePromise = undefined;
   }
 }
-
 export default AutocompleteLruCache;