add aden's requested changes

src/test/mocks/webextension-polyfill.ts

@@ -0,0 +1,35 @@
+const storage = new Map<string, unknown>();
+
+const local = {
+  get: jest.fn(async (keys?: string | string[] | null) => {
+    if (keys == null) {
+      return Object.fromEntries(storage);
+    }
+    if (typeof keys === "string") {
+      return keys in storage ? { [keys]: storage.get(keys) } : {};
+    }
+    const out: Record<string, unknown> = {};
+    for (const key of keys) {
+      if (storage.has(key)) out[key] = storage.get(key);
+    }
+    return out;
+  }),
+  set: jest.fn(async (items: Record<string, unknown>) => {
+    for (const [k, v] of Object.entries(items)) storage.set(k, v);
+  }),
+  remove: jest.fn(async (keys: string | string[]) => {
+    const list = Array.isArray(keys) ? keys : [keys];
+    for (const key of list) storage.delete(key);
+  }),
+};
+
+export default {
+  storage: { local },
+};
+
+export function __resetBrowserStorageMock() {
+  storage.clear();
+  local.get.mockClear();
+  local.set.mockClear();
+  local.remove.mockClear();
+}