Testing text contrast in react-native

Not actually sure, it is should be done with jest. But how to ensure, that found text on the screen is visible? There are my short files for example: (setted color of text to be same as bg, but it passes)

in text format to you, if you want copy/paste

export default () => (
  <SafeAreaView style={ style.container }>
    <Text style={ style.text }>loading..</Text>
  </SafeAreaView>
)

,

test('In Loading screen, there is "loading" visible label', () => {
  const { getByText } = render(
    <Loading />
  )

  getByText(/loading/) // exact 1 (not 0, not >)
})