feat: add auto update support

src/main/runtime/update/app-updater.test.ts

@@ -0,0 +1,55 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { configureAutoUpdater, type ElectronAutoUpdaterLike } from './app-updater';
+
+type UpdaterLogger = {
+  info: (message: string) => void;
+  debug: (message: string) => void;
+  warn: (message: string) => void;
+  error: (message: string) => void;
+};
+
+test('configureAutoUpdater disables eager update behavior and suppresses info logging', () => {
+  const logged: string[] = [];
+  const updater: ElectronAutoUpdaterLike & { logger?: UpdaterLogger | null } = {
+    autoDownload: true,
+    allowPrerelease: true,
+    allowDowngrade: true,
+    logger: null,
+    checkForUpdates: async () => null,
+    downloadUpdate: async () => [],
+    quitAndInstall: () => {},
+  };
+
+  configureAutoUpdater(updater, (message) => logged.push(message));
+
+  assert.equal(updater.autoDownload, false);
+  assert.equal(updater.allowPrerelease, false);
+  assert.equal(updater.allowDowngrade, false);
+  assert.ok(updater.logger);
+
+  updater.logger.info('Checking for update');
+  updater.logger.debug('Generated new staging user ID');
+  updater.logger.warn('metadata missing');
+  updater.logger.error('download failed');
+
+  assert.deepEqual(logged, ['metadata missing', 'download failed']);
+});
+
+test('configureAutoUpdater allows prereleases only for the prerelease channel', () => {
+  const updater: ElectronAutoUpdaterLike = {
+    autoDownload: true,
+    allowPrerelease: false,
+    allowDowngrade: true,
+    logger: null,
+    checkForUpdates: async () => null,
+    downloadUpdate: async () => [],
+    quitAndInstall: () => {},
+  };
+
+  configureAutoUpdater(updater, () => {}, 'prerelease');
+  assert.equal(updater.allowPrerelease, true);
+
+  configureAutoUpdater(updater, () => {}, 'stable');
+  assert.equal(updater.allowPrerelease, false);
+});