Allow simple extensions for registering MCPservers (#890)

packages/cli/src/config/extension.test.ts

@@ -0,0 +1,80 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { vi } from 'vitest';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import {
+  EXTENSIONS_CONFIG_FILENAME,
+  EXTENSIONS_DIRECTORY_NAME,
+  loadExtensions,
+} from './extension.js';
+
+vi.mock('os', async (importOriginal) => {
+  const os = await importOriginal<typeof import('os')>();
+  return {
+    ...os,
+    homedir: vi.fn(),
+  };
+});
+
+describe('loadExtensions', () => {
+  let tempWorkspaceDir: string;
+  let tempHomeDir: string;
+
+  beforeEach(() => {
+    tempWorkspaceDir = fs.mkdtempSync(
+      path.join(os.tmpdir(), 'gemini-cli-test-workspace-'),
+    );
+    tempHomeDir = fs.mkdtempSync(
+      path.join(os.tmpdir(), 'gemini-cli-test-home-'),
+    );
+    vi.mocked(os.homedir).mockReturnValue(tempHomeDir);
+  });
+
+  afterEach(() => {
+    fs.rmSync(tempWorkspaceDir, { recursive: true, force: true });
+    fs.rmSync(tempHomeDir, { recursive: true, force: true });
+  });
+
+  it('should deduplicate extensions, prioritizing the workspace directory', () => {
+    // Create extensions in the workspace
+    const workspaceExtensionsDir = path.join(
+      tempWorkspaceDir,
+      EXTENSIONS_DIRECTORY_NAME,
+    );
+    fs.mkdirSync(workspaceExtensionsDir, { recursive: true });
+    createExtension(workspaceExtensionsDir, 'ext1', '1.0.0');
+    createExtension(workspaceExtensionsDir, 'ext2', '2.0.0');
+
+    // Create extensions in the home directory
+    const homeExtensionsDir = path.join(tempHomeDir, EXTENSIONS_DIRECTORY_NAME);
+    fs.mkdirSync(homeExtensionsDir, { recursive: true });
+    createExtension(homeExtensionsDir, 'ext1', '1.1.0'); // Duplicate that should be ignored
+    createExtension(homeExtensionsDir, 'ext3', '3.0.0');
+
+    const extensions = loadExtensions(tempWorkspaceDir);
+
+    expect(extensions).toHaveLength(3);
+    expect(extensions.find((e) => e.name === 'ext1')?.version).toBe('1.0.0'); // Workspace version should be kept
+    expect(extensions.find((e) => e.name === 'ext2')?.version).toBe('2.0.0');
+    expect(extensions.find((e) => e.name === 'ext3')?.version).toBe('3.0.0');
+  });
+});
+
+function createExtension(
+  extensionsDir: string,
+  name: string,
+  version: string,
+): void {
+  const extDir = path.join(extensionsDir, name);
+  fs.mkdirSync(extDir);
+  fs.writeFileSync(
+    path.join(extDir, EXTENSIONS_CONFIG_FILENAME),
+    JSON.stringify({ name, version }),
+  );
+}