const signUpForm = findRenderedComponentWithType(app, SignUpForm)
signUpForm.props.change('username', 'Joe')
signUpForm.props.change('password', 'isVeryAngryBecauseHeCantSignUp')
Simulate.submit(signUpForm.refs.submitButton)

state {
  registeredFields: [
    { name: 'username', type: 'Field' },
    { name: 'password', type: 'Field' }
  ],
  fields: { username: { touched: true }, password: { touched: true } },
  anyTouched: true,
  submitting: true
}