test_activate.js

const makeServiceWorkerEnv = require('service-worker-mock');

describe('Service worker', () => {
  beforeEach(() => {
    Object.assign(global, makeServiceWorkerEnv());
    jest.resetModules();
  });

  it('should delete old caches on activate', async () => {
      require('../sw.js');

      // Create old cache
      await self.caches.open('OLD_CACHE');
      expect(self.snapshot().caches.OLD_CACHE).toBeDefined();

      // Activate and verify old cache is removed
      await self.trigger('activate');
      expect(self.snapshot().caches.OLD_CACHE).toBeUndefined();
  });
});