add test for app sagas

src/sagas/app.test.ts

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2021 The Pybricks Authors
+
+import { AsyncSaga, delay } from '../../test';
+import { reload } from '../actions/app';
+import app from './app';
+
+test('reload', async () => {
+    const saga = new AsyncSaga(app);
+
+    // mock registration as if service worker was register on app startup
+    const registration: Partial<ServiceWorkerRegistration> = {
+        unregister: jest.fn(),
+    };
+
+    // @ts-expect-error: navigator.serviceWorker is not implemented in JSDOM
+    navigator.serviceWorker = {
+        getRegistrations: jest.fn().mockResolvedValue([registration]),
+    };
+
+    // @ts-expect-error: JSDOM implementation of location.reload() causes error
+    delete window.location;
+    // @ts-expect-error: JSDOM implementation of location.reload() causes error
+    window.location = {
+        reload: jest.fn(),
+    };
+
+    saga.put(reload());
+
+    // yield to allow generators to complete
+    await delay(0);
+
+    expect(registration.unregister).toHaveBeenCalled();
+    expect(location.reload).toHaveBeenCalled();
+
+    await saga.end();
+});

src/sagas/app.ts

@@ -5,8 +5,6 @@ import { call, takeEvery } from 'redux-saga/effects';
 import { AppActionType } from '../actions/app';
 
 function* reload(): Generator {
-    console.log('reload');
-
     // unregister the service worker so that when the page reloads, it uses
     // the new version
     const registrations = (yield call(() =>