How to mock Picker and Picker.Item with jest in React-Native?

Question

I am trying to snapshot test this snippet of code: ``` import React, { Component } from 'react'; import { Picker, } from 'react-native'; export default class TestComponent extends Component { render() { return ( ); } } ``` My test looks like this right now: ``` import 'react-native'; import React from 'react'; import TestComponent from './TestComponent'; import renderer from 'react-test-renderer'; describe('TestComponent', () => { const asset = { type: 'car', } it('renders correctly', () => { const tree = renderer.create( ).toJSON(); expect(tree).toMatchSnapshot(); }); }) ``` My problem is that I get: ``` TypeError: Cannot read property '_tag' of undefined ``` I think that I should m…

Accepted Answer

Created a github issue as well and here is a working answer:

```
jest.mock('Picker', () => {
  const Picker = class extends Component {
    static Item = props => React.createElement('Item', props, props.children);
    static propTypes = { children: React.PropTypes.any };

render() {
      return React.createElement('Picker', this.props, this.props.children);
    }
  }
  return Picker;
})
```

How to mock Picker and Picker.Item with jest in React-Native?

Solution

Problem