feat(test): Increase test coverage across CLI and Core packages (#1089)

packages/core/src/code_assist/oauth2.test.ts

@@ -0,0 +1,92 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi } from 'vitest';
+import { webLoginClient } from './oauth2.js';
+import { OAuth2Client } from 'google-auth-library';
+import http from 'http';
+import open from 'open';
+import crypto from 'crypto';
+
+vi.mock('google-auth-library');
+vi.mock('http');
+vi.mock('open');
+vi.mock('crypto');
+
+describe('oauth2', () => {
+  it('should perform a web login', async () => {
+    const mockAuthUrl = 'https://example.com/auth';
+    const mockCode = 'test-code';
+    const mockState = 'test-state';
+    const mockTokens = {
+      access_token: 'test-access-token',
+      refresh_token: 'test-refresh-token',
+    };
+
+    const mockGenerateAuthUrl = vi.fn().mockReturnValue(mockAuthUrl);
+    const mockGetToken = vi.fn().mockResolvedValue({ tokens: mockTokens });
+    const mockSetCredentials = vi.fn();
+    const mockOAuth2Client = {
+      generateAuthUrl: mockGenerateAuthUrl,
+      getToken: mockGetToken,
+      setCredentials: mockSetCredentials,
+    } as unknown as OAuth2Client;
+    vi.mocked(OAuth2Client).mockImplementation(() => mockOAuth2Client);
+
+    vi.spyOn(crypto, 'randomBytes').mockReturnValue(mockState as never);
+    vi.mocked(open).mockImplementation(async () => ({}) as never);
+
+    let requestCallback!: (
+      req: http.IncomingMessage,
+      res: http.ServerResponse,
+    ) => void;
+    const mockHttpServer = {
+      listen: vi.fn((port: number, callback?: () => void) => {
+        if (callback) {
+          callback();
+        }
+      }),
+      close: vi.fn((callback?: () => void) => {
+        if (callback) {
+          callback();
+        }
+      }),
+      on: vi.fn(),
+      address: () => ({ port: 1234 }),
+    };
+    vi.mocked(http.createServer).mockImplementation((cb) => {
+      requestCallback = cb as (
+        req: http.IncomingMessage,
+        res: http.ServerResponse,
+      ) => void;
+      return mockHttpServer as unknown as http.Server;
+    });
+
+    const clientPromise = webLoginClient();
+
+    // Wait for the server to be created
+    await new Promise((resolve) => setTimeout(resolve, 0));
+
+    const mockReq = {
+      url: `/oauth2callback?code=${mockCode}&state=${mockState}`,
+    } as http.IncomingMessage;
+    const mockRes = {
+      writeHead: vi.fn(),
+      end: vi.fn(),
+    } as unknown as http.ServerResponse;
+
+    if (requestCallback) {
+      await requestCallback(mockReq, mockRes);
+    }
+
+    const client = await clientPromise;
+
+    expect(open).toHaveBeenCalledWith(mockAuthUrl);
+    expect(mockGetToken).toHaveBeenCalledWith(mockCode);
+    expect(mockSetCredentials).toHaveBeenCalledWith(mockTokens);
+    expect(client).toBe(mockOAuth2Client);
+  });
+});