old_contents: var expect = require('chai').expect,
  	supertest = require('supertest'),
  	app = require('../app/server');
  
  describe('test api', function () {
  	it('should return 200', function (done) {
  		supertest(app)
  			.get('/echo/1')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				done();
  			});
  	});
  
  	it('should return 200 with echo value', function (done) {
  		var echoValue = 'hi';
  		supertest(app)
  			.get('/echo/' + echoValue)
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.echo).to.equal(echoValue);
  				done();
  			});
  	});
  
  	it('should return sum of added numbers', function (done) {
  		supertest(app)
  			.get('/api/add/1/2')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.sum).to.equal(3);
  				done();
  			});
  	});
  
  	it('should return sum of added number with negative number', function (done) {
  		supertest(app)
  			.get('/api/add/-3/2')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.sum).to.equal(-1);
  				done();
  			});
  	});
  });
  
new_contents: var describe = require('mocha/lib/mocha.js').describe,
  	it = require('mocha/lib/mocha.js').it,
  	expect = require('chai').expect,
  	supertest = require('supertest'),
  	app = require('../app/server');
  
  describe('test api', function () {
  	it('should return 200', function (done) {
  		supertest(app)
  			.get('/echo/1')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				done();
  			});
  	});
  
  	it('should return 200 with echo value', function (done) {
  		var echoValue = 'hi';
  		supertest(app)
  			.get('/echo/' + echoValue)
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.echo).to.equal(echoValue);
  				done();
  			});
  	});
  
  	it('should return sum of added numbers', function (done) {
  		supertest(app)
  			.get('/api/add/1/2')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.sum).to.equal(3);
  				done();
  			});
  	});
  
  	it('should return sum of added number with negative number', function (done) {
  		supertest(app)
  			.get('/api/add/-3/2')
  			.expect(200)
  			.end(function (err, res) {
  				expect(res.status).to.equal(200);
  				expect(res.body.sum).to.equal(-1);
  				done();
  			});
  	});
  });
  
subject: add mocha describe and it dependencies