message: update margin and padding tests for FlexItem
diff: @@ -2,7 +2,7 @@ import React from 'react'
  import FlexItem from '../FlexItem'
  import {FLEX_ITEM} from '../system-props'
  import theme from '../theme'
  -import {render} from '../utils/testing'
  +import {render, renderStyles} from '../utils/testing'
  describe('FlexItem', () => {
  it('is a system component', () => {
  @@ -27,11 +27,15 @@ describe('FlexItem', () => {
  expect(item).toMatchSnapshot()
  })
  - xit('margin utility', () => {
  - expect(render(<FlexItem m={2} them={theme} />)).toMatchSnapshot()
  + it('respects margin utility prop', () => {
  + expect(renderStyles(<FlexItem m={4} />)).toMatchKeys({
  + 'margin': `${theme.space[4]}px`
  + })
  })
  - xit('padding utility', () => {
  - expect(render(<FlexItem p={1} them={theme} />)).toMatchSnapshot()
  + it('respects padding utility prop', () => {
  + expect(renderStyles(<FlexItem p={4} />)).toMatchKeys({
  + 'padding': `${theme.space[4]}px`
  + })
  })
  })
  