text: 'use strict'
  
  // NPM Modules
  import chai from 'chai'
  
  // Algorithm
  import { hasDuplicateCharacters } from '../../es'
  
  const expect = chai.expect
  
  // Test
  describe('Has Duplicate Characters Algorithm: hasDuplicateCharacters(string)', () => {
    it('Should correctly return true or false depending on whether the input string has duplicate characters', () => {
      expect(hasDuplicateCharacters('dat')).to.eql(false)
      expect(hasDuplicateCharacters('ma')).to.eql(false)
      expect(hasDuplicateCharacters('cat')).to.eql(false)
      expect(hasDuplicateCharacters('hello')).to.eql(true)
      expect(hasDuplicateCharacters('motto')).to.eql(true)
    })
    it('Should return null when no input is provided', () => {
      expect(hasDuplicateCharacters()).to.eql(null)
    })
  })
  