is there another way to mock component's mapDispatchToProps when using Jest - reactjs

Question

I currently have a component like so:
import React, { Component } from 'react';
import { connect } from 'react-redux';
import { getDataAction } from ' './my-component';
export class MyComponent extends { Component } {
componentWillMount() {
this.props.getData();
}
render(){
<div>
this.props.title
</div>
}
}
const mapStateToProps = (state) => ({
title: state.title
});
const mapDispatchToProps = (dispatch) ({
getData() {
dispatch(getDataAction());
}
});
export default connect(mapStateToProps, mapDispatchToProps)(MyComponent)
and I am trying to shallow render test it using jest and enzyme.
test:
import React from 'react';
import { shallow } from 'enzyme';
import { MyComponent } from './index';
it('renders without crashing', () => {
shallow(<MyComponent getData={jest.fn()} />);
});
My question is, is this the conventional way to mock? Jest official docs don't mention specifically about mocking props and this post Using Jest to mock a React component with props is about testing with full mounting instead.
Is there another way to mock dispatchToProps? In this example there is only one, but what if I have a lot of functions in dispatchToProps?
Side Question: in my real file, I have a reference to a value like this.props.information.value which I expect to throw an error like cannot get value of undefined since information is not mocked/defined, but it doesn't. It's only when functions are not present that an error is thrown.

Answer 1

You can export mapDispatchToProps and write tests for it by importing it in your tests.
Add export { mapDispatchToProps }; at the end of your MyComponent.js
Create MyComponent.tests.js file beside MyComponent.js
import configureMockStore from 'redux-mock-store';
import thunkMiddleware from 'redux-thunk';
import { mapDispatchToProps } from './MyComponent';
const configMockStore = configureMockStore([thunkMiddleware]);
const storeMockData = {};
const mockStore = configMockStore(storeMockData);
describe('mapDispatchToProps', () => {
it('should map getDataAction action to getData prop', () => {
// arrange
const expectedActions = [getDataAction.type];
const dispatchMappedProps = mapDispatchToProps(mockStore.dispatch);
// act
dispatchMappedProps.getData();
// assert
expect(mockStore.getActions().map(action => action.type)).toEqual(expectedActions);
}
});
Here I have used thunk, just to let you know that how to do it if there are middlewares configured in your store setup.
Here getDataAction can also be a function instead of a simple action like { type: 'FETCH_DATA' } if you are using middlewares like thunks. However, the approach to test is same except that you will create expectedActions with explicit action types like const expectedActions = ['FETCH_CONTACTS']
Here FETCH_CONTACT is another action dispatched in your thunk i.e getDataAction