text: 
  var express = require('..');
  var request = require('supertest');
  
  describe('res', function(){
    describe('.set(field, value)', function(){
      it('should set the response header field', function(done){
        var app = express();
  
        app.use(function(req, res){
          res.set('Content-Type', 'text/x-foo; charset=utf-8').end();
        });
  
        request(app)
        .get('/')
        .expect('Content-Type', 'text/x-foo; charset=utf-8')
        .end(done);
      })
  
      it('should coerce to a string', function (done) {
        var app = express();
  
        app.use(function (req, res) {
          res.set('X-Number', 123);
          res.end(typeof res.get('X-Number'));
        });
  
        request(app)
        .get('/')
        .expect('X-Number', '123')
        .expect(200, 'string', done);
      })
    })
  
    describe('.set(field, values)', function(){
      it('should set multiple response header fields', function(done){
        var app = express();
  
        app.use(function(req, res){
          res.set('Set-Cookie', ["type=ninja", "language=javascript"]);
          res.send(res.get('Set-Cookie'));
        });
  
        request(app)
        .get('/')
        .expect('["type=ninja","language=javascript"]', done);
      })
  
      it('should coerce to an array of strings', function (done) {
        var app = express();
  
        app.use(function (req, res) {
          res.set('X-Numbers', [123, 456]);
          res.end(JSON.stringify(res.get('X-Numbers')));
        });
  
        request(app)
        .get('/')
        .expect('X-Numbers', '123, 456')
        .expect(200, '["123","456"]', done);
      })
  
      it('should not set a charset of one is already set', function (done) {
        var app = express();
  
        app.use(function (req, res) {
          res.set('Content-Type', 'text/html; charset=lol');
          res.end();
        });
  
        request(app)
        .get('/')
        .expect('Content-Type', 'text/html; charset=lol')
        .expect(200, done);
      })
  
      it('should throw when Content-Type is an array', function (done) {
        var app = express()
  
        app.use(function (req, res) {
          res.set('Content-Type', ['text/html'])
          res.end()
        });
  
        request(app)
        .get('/')
        .expect(500, /TypeError: Content-Type cannot be set to an Array/, done)
      })
    })
  
    describe('.set(object)', function(){
      it('should set multiple fields', function(done){
        var app = express();
  
        app.use(function(req, res){
          res.set({
            'X-Foo': 'bar',
            'X-Bar': 'baz'
          }).end();
        });
  
        request(app)
        .get('/')
        .expect('X-Foo', 'bar')
        .expect('X-Bar', 'baz')
        .end(done);
      })
  
      it('should coerce to a string', function (done) {
        var app = express();
  
        app.use(function (req, res) {
          res.set({ 'X-Number': 123 });
          res.end(typeof res.get('X-Number'));
        });
  
        request(app)
        .get('/')
        .expect('X-Number', '123')
        .expect(200, 'string', done);
      })
    })
  })
  