text: (() => {
    'use strict';
  
    const
      expect = require('expect'),
      deepFreeze = require('deep-freeze'),
      immutable = require('../src/immutable-array');
  
    describe('Avoid Array Mutation', () => {
  
      it('addCounter must return new list without mutating the existing list', () => {
        const
          listBefore = [1],
          listAfter = [1, 0];
  
        deepFreeze(listBefore);
  
        expect(
          immutable.addCounter(listBefore)
        ).toEqual(listAfter);
  
      });
  
      it('removeCounter must return new list without mutating the existing list', () => {
        const
          listBefore = [0, 10, 20],
          listAfter = [0, 20];
  
        deepFreeze(listBefore);
  
        expect(
          immutable.removeCounter(listBefore, 1)
        ).toEqual(listAfter);
  
      });
  
      it('incCounter must return new list without mutating the existing list', () => {
        const
          listBefore = [0, 10, 20],
          listAfter = [0, 11, 20];
  
        deepFreeze(listBefore);
  
        expect(
          immutable.incCounter(listBefore, 1)
        ).toEqual(listAfter);
  
      });
  
    });
  
  })();
  