ButtonTest.js

import test from 'ava'
import React from 'react'
import Button from '../Button'
import { shallow } from 'enzyme'

test('component structure', t => {
  const wrapper = shallow(<Button onPress={() => {}} text='hi' />)

  t.is(wrapper.name(), 'TouchableOpacity') // root component
  t.is(wrapper.children().length, 1) // has 1 child
  t.is(wrapper.children().first().name(), 'Text')
})