👀 Views: 72 💬 Answers: 1 📅 Created: 2025-06-17

jest unit-testing node.js JavaScript

I'm reviewing some code and I'm trying to unit test a method in my Node.js service that makes an external API call to fetch user data... I'm using Jest for testing, but I'm having difficulty mocking the API response effectively. Here's the relevant code snippet: ```javascript const axios = require('axios'); class UserService { async getUserData(userId) { const response = await axios.get(`https://api.example.com/users/${userId}`); return response.data; } } module.exports = UserService; ``` My test file looks like this: ```javascript const UserService = require('./UserService'); const axios = require('axios'); jest.mock('axios'); describe('UserService', () => { it('should fetch user data', async () => { const userService = new UserService(); const mockData = { id: 1, name: 'John Doe' }; axios.get.mockResolvedValue({ data: mockData }); const data = await userService.getUserData(1); expect(data).toEqual(mockData); }); }); ``` When I run my tests, I occasionally get a timeout behavior, and Jest reports that the promise was never resolved. Other times, it passes, which makes me suspect that the mock is not consistently set up properly. I've tried ensuring that `jest.mock('axios')` is placed correctly, and I've also tried using `jest.clearAllMocks()` before each test to ensure clean state, but I still face intermittent issues. I'm using Jest version 27.0.0. Is there something I'm missing in my test setup or approach that could be causing this inconsistency? Any ideas would be greatly appreciated! For context: I'm using Javascript on macOS. Any help would be greatly appreciated!