Counter.js

import React from 'react'
import { connect } from 'react-redux'

import { increment, decrement } from './actions'

export const Counter = ({counter, increment, decrement}) => {
  return (
    <div>
      <p className='counter'>Counter: {counter}</p>
      <button className='increment' onClick={() => increment(10)}>+</button>
      <button className='decrement' onClick={() => decrement(5)}>-</button>
    </div>
  )
}

const mapStateToProps = (state) => {
  return {
    counter: state.counter
  }
}

const mapDispatchToProps = (dispatch) => {
  return {
    increment: (value) => dispatch(increment(value)),
    decrement: (value) => dispatch(decrement(value))
  }
}

export default connect(mapStateToProps, mapDispatchToProps)(Counter)

Counter.test.js

import React from 'react'
import { configure, shallow } from 'enzyme'
import Adapter from 'enzyme-adapter-react-16'

configure({ adapter: new Adapter() })

import { Counter } from './Counter'

describe('<Counter />', () => {
  it('should mount', () => {
    const props = {
      counter: 10,
      increment: () => 1,
      decrement: () => 1
    }

    const wrapper = shallow(<Counter {...props} />)
    expect(wrapper.length).toEqual(1)
  })

  it('should call increment', () => {
    const props = {
      counter: 10,
      increment: () => jest.fn(),
      decrement: () => jest.fn()
    }

    const wrapper = shallow(<Counter {...props} />)

    wrapper.find('.increment').simulate('click')
    expect(props.increment.mock.calls.length).toEqual(1)
  })
})

O erro ocorre na linha 31 do Counter.test.js.
A msg recebida é: TypeError: Cannot read property 'calls' of undefined