message: add system props tests
diff: import React from 'react'
  import {Button, ButtonPrimary, ButtonDanger, ButtonLink, ButtonOutline} from '..'
  import {render, rendersClass} from '../utils/testing'
  +import {COMMON} from '../system-props'
  function noop() {}
  @@ -9,6 +10,10 @@ describe('Button', () => {
  expect(render(<Button />).type).toEqual('button')
  })
  + it('implements common system props', () => {
  + expect(Button).toImplementSystemProps(COMMON)
  + })
  +
  xit('renders children', () => {
  expect(
  render(
  @@ -61,6 +66,10 @@ describe('ButtonPrimary', () => {
  expect(render(<ButtonPrimary />).type).toEqual('button')
  expect(render(<ButtonPrimary />).props.className).toContain('btn-primary')
  })
  +
  + it('implements common system props', () => {
  + expect(ButtonPrimary).toImplementSystemProps(COMMON)
  + })
  })
  describe('ButtonDanger', () => {
  @@ -69,6 +78,10 @@ describe('ButtonDanger', () => {
  expect(render(<ButtonDanger />).props.className).toContain('btn-danger')
  })
  + it('implements common system props', () => {
  + expect(ButtonDanger).toImplementSystemProps(COMMON)
  + })
  +
  xit('renders children', () => {
  expect(
  render(
  @@ -91,6 +104,10 @@ describe('ButtonLink', () => {
  expect(render(<ButtonLink />).type).toEqual('button')
  expect(render(<ButtonLink />).props.className).toContain('btn-link')
  })
  +
  + it('implements common system props', () => {
  + expect(ButtonLink).toImplementSystemProps(COMMON)
  + })
  })
  describe('ButtonOutline', () => {
  @@ -98,4 +115,8 @@ describe('ButtonOutline', () => {
  expect(render(<ButtonOutline />).type).toEqual('button')
  expect(render(<ButtonOutline />).props.className).toContain('btn-outline')
  })
  +
  + it('implements common system props', () => {
  + expect(ButtonOutline).toImplementSystemProps(COMMON)
  + })
  })
  