text: 
  var co = require('..');
  var fs = require('fs');
  
  var read = co.wrap(fs.readFile);
  
  describe('co.wrap(fn)', function(){
    it('should return a thunk', function(done){
      co(function *(){
        var a = yield read('index.js', 'utf8');
        var b = yield read('Makefile');
        a.should.include('exports');
        b.should.be.an.instanceof(Buffer);
        done();
      });
    })
  })
  