Index: node_modules/simple-update-notifier/src/cache.spec.ts
===================================================================
--- node_modules/simple-update-notifier/src/cache.spec.ts	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
+++ node_modules/simple-update-notifier/src/cache.spec.ts	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
@@ -0,0 +1,17 @@
+import { createConfigDir, getLastUpdate, saveLastUpdate } from './cache';
+
+createConfigDir();
+
+jest.useFakeTimers().setSystemTime(new Date('2022-01-01'));
+
+const fakeTime = new Date('2022-01-01').getTime();
+
+test('can save update then get the update details', () => {
+  saveLastUpdate('test');
+  expect(getLastUpdate('test')).toBe(fakeTime);
+});
+
+test('prefixed module can save update then get the update details', () => {
+  saveLastUpdate('@alexbrazier/test');
+  expect(getLastUpdate('@alexbrazier/test')).toBe(fakeTime);
+});