describe('getUserAddress', () => {
  const user1: User = { id: 1, name: 'Alice', age: 25 }
  const user2: User = { id: 2, name: 'Bob', age: 30, address: '123 Main St' }
  const user3: User = { id: 3, name: 'Charlie', age: 35, address: null }

  it('returns O.none if user has no address', () => {
    const result = getUserAddress(user1)
    expect(result).toEqual({ _tag: 'None' })
  })

  it('returns some with the address if user has an address', () => {
    const result = getUserAddress(user2)
    expect(result).toEqual({ _tag: 'Some', value: '123 Main St' })
  })

  it('returns O.none if user has a null address', () => {
    const result = getUserAddress(user3)
    expect(result).toEqual({ _tag: 'None' })
  })
})