test('sends welcome email to new user', async () => {
  const user = await userService.register({
    email: 'test@example.com',
    name: 'Alice'
  })

  // Actually sends email - slow, unreliable, costs money
  // Fails if email server is down
  // Clutters real inbox or spam folder
  const emails = await checkEmailInbox('test@example.com')
  expect(emails).toContainEqual(expect.objectContaining({
    subject: 'Welcome to our platform!'
  }))
})

test('sends welcome email to new user', async () => {
  // Arrange
  const mockEmailService = {
    send: jest.fn().mockResolvedValue({ success: true })
  }
  const userService = new UserService({ emailService: mockEmailService })

  // Act
  await userService.register({
    email: 'test@example.com',
    name: 'Alice'
  })

  // Assert
  expect(mockEmailService.send).toHaveBeenCalledWith({
    to: 'test@example.com',
    subject: 'Welcome to our platform!',
    body: expect.stringContaining('Alice')
  })
})