describe('Utils', () => {
  let arr;
  const { join } = require('./../utils.js');
  beforeEach(() => {
    arr = [[100, 'a'], [20, 'b'], [6, 'c'], [4, 'd']];

  });
  describe('join should', () => {
    it('return a string', () => {
      // Arrange & Act
      const str =arr.join(',');
      // Assert
      expect(arr).not.toEqual(str);
    });

    it(`return a string concated with: ${','} `, () => {
        // Arrange & Act
        const str = arr.join(',');

        // Assert



        let i = 0;
        while (i < arr.length)
        {
            expect(str[i]).toEqual(arr.join(',')[i]);
            i++;
        }
      });
    });
  });