Jest snapshot using a ListView fails with unique "key" error

[luisfcofv]

Adding a snapshot test using a ListView fails with the following error:

console.error node_modules/react-native/Libraries/Core/ExceptionsManager.js:71
 Warning: Each child in an array or iterator should have a unique "key" prop.
 Check the render method of `ScrollViewMock`.
 It was passed a child from ListViewMock. See https://fb.me/react-warning-keys for more information.

Code snippet:

export class App extends Component {
 state = {
 dataSource: new ListView.DataSource({ rowHasChanged: (r1, r2) => r1 !== r2 }),
 };

 componentWillReceiveProps({ results }) {
 this.setState({
 dataSource: this.state.dataSource.cloneWithRows(results),
 });
 }

 renderHeader = () => (
 <Header />
 );

 renderRow = resultInfo => (
 <ResultCell resultInfo={resultInfo} />
 )

 renderFooter = () => {
 const { results } = this.props;
 if (results.length >= results.totalItems) {
 return null;
 }

 return <ActivityIndicator />;
 }

 render() {
 return (
 <ListView
 dataSource={this.state.dataSource}
 enableEmptySections
 renderHeader={this.renderHeader}
 onScroll={Keyboard.dismiss}
 renderRow={this.renderRow}
 renderFooter={this.renderFooter}
 />
 );
 }
}

Test:

test('renders correctly', () => {
 const tree = renderer.create(
 <App results={[]} />
 ).toJSON();
 expect(tree).toMatchSnapshot();
});

react native: 0.42.0
jest: 19.0.2
yarn: 0.21.3
os: macOS

[luisfcofv]

Removing renderFooter & renderHeader seems to fix the problem; however, I need those props

[hramos]

Hi there! This issue is being closed because it has been inactive for a while. Maybe the issue has been fixed in a recent release, or perhaps it is not affecting a lot of people. Either way, we're automatically closing issues after a period of inactivity. Please do not take it personally!

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[spinningarrow]

I'm seeing this issue as well with React Native 0.47.1. Is there a way to fix it?

[keijohyttinen]

At least warning disappeared for me with a workaround mentioned at
#12225

[mohamede1945]

For me, the workaround was to add key="footer" to the footer and you can do the same for header if the warning didn't go away.