text: /* eslint-env jest */
  
  import reducer from '../reducer';
  import { add, minus } from '../actions';
  
  test('should make 0 as default amount', () => {
    expect(reducer(undefined, { type: 'notexist' })).toEqual({
      amount: 0,
    });
  });
  
  test('should add amount for add() action', () => {
    const state = { amount: 100 };
    expect(reducer(state, add())).toEqual({
      amount: 101,
    });
  });
  
  test('should minus amount for minu() action', () => {
    const state = { amount: 100 };
    expect(reducer(state, minus())).toEqual({
      amount: 99,
    });
  });
  