Mocking children components with Jest - does this make sense?

icon.js

import React from 'react'

export default class Icon extends React.Component {

  render () {
    const {type, className} = this.props
    return (
      <i 
        className={`fa fa-${type} fa-fw ${className}`}
        {...this.props}
      />
    )
  }
}

icon.test.js

/* global describe, it, expect */

import React from 'react'
import renderer from 'react-test-renderer'

import Icon from '../../lib/components/icon'

describe('Icon', () => {
  it('renders correctly', () => {
    const tree = renderer.create(
      <Icon
        type='pencil'
        className='test'
        />
    ).toJSON()
    expect(tree).toMatchSnapshot()
  })
})

project.js

import React from 'react'

import Icon from './icon'

export default class Project extends React.Component {

  render () {
    const {children} = this.props
    return (
      <div>
        <div
          className='ProjectTitle'
          >
          <Icon type='list' />
          <a href='#'>A Link</a>
        </div>
        {children}
      </div>
    )
  }
}

project.test.js

import React from 'react'
import renderer from 'react-test-renderer'

import { mockComponent } from '../../testUtils'

jest.mock('../../lib/components/icon', () => { return mockComponent('Icon') })

import Project from '../../lib/components/project'

describe('Project', () => {
  it('renders correctly', () => {
    const tree = renderer.create(
      <Project/>
    ).toJSON()
    expect(tree).toMatchSnapshot()
  })
})

testUtils.js

import React from 'react'

export function mockComponent (componentName) {
  return (props) => {
    return (
      <mocked originalComponent={componentName} {...props}>{props.children}</mocked>
    )
  }
}

export function mockNamedComponents (componentNames) {
  const mockedComponents = {}
  for (let i = 0; i < componentNames.length; i++) {
    const name = componentNames[i]
    mockedComponents[name] = mockComponent(name)
  }
  return mockedComponents
}

TypeError: Cannot read property 'mockComponent' of undefined

how we can write test cases for the child component if we use above child mocking example