text: 'use strict';
  let chai = require('chai');
  let expect = chai.expect;
  let Calculator = require('../Calculator');
  
  describe( "Calculator", function(){
      let calculator;
      beforeEach( function(){
          calculator = new Calculator();
      } );
      it( "adds 1 and 2", function(){
          expect( calculator.add( 1, 2 ) ).to.equal( 3 );
      } );
      it( "subtracts 2 from 9", function(){
          expect( calculator.subtract( 9, 2 ) ).to.equal( 7 );
      } );
      it( "multiplies 4 and 3", function(){
          expect( calculator.multiply( 4, 3 ) ).to.equal( 12 );
      } );
      it( "divides 10 by 2", function(){
          expect( calculator.divide( 10, 2 ) ).to.equal( 5 );
      } );
      it( "does not divide by 0", function(){
          expect( calculator.divide( 5, 0 ) ).to.deep.equal( NaN );
      } );
  } );
  
  