React Test Renderer: findAllByProps return double of what It should find when looking for testID in React Native

Question

I'm using React Test Renderer with Jest to test my React Native app.

Here is a simple code example of what I'm doing:

it('renders one text', () => {
  const text = 'bar';
  const instance = renderer.create(
    <View>
      <Text testID="foo">{text}</Text>
    </View>
  ).root;
  expect(instance.findAllByProps({ testID: 'foo' }).length).toEqual(1);
});

it('renders two texts', () => {
  const text = 'bar';
  const instance = renderer.create(
    <View>
      <Text testID="foo">{text}</Text>
      <Text testID="foo">{text}</Text>
    </View>
  ).root;
  expect(instance.findAllByProps({ testID: 'foo' }).length).toEqual(2);
});

The first test fails saying:

Expected: 1
Received: 2

And the second test also fails:

Expected: 2
Received: 4

Why does react test renderer using findAllByProps find double the instances?

PS: As a sanity check I also tried findByProps which works:

it('renders one text', () => {
  const text = 'bar';
  const instance = renderer.create(
    <View>
      <Text testID="foo">{text}</Text>
    </View>
  ).root;
  expect(instance.findByProps({ testID: 'foo' }).props.children).toEqual(text);
});

Answer 1

There is unresolved issue on react-native

Currently the only work-around is:

const findAllByTestID = (instance) => instance.findAll(el => el.props.testID === 'foo' && el.type === 'Text');

expect(findAllByTestID(instance).length).toEqual(2);