text: var http = require('http'),
      assert = require('assert');
  
  var opts = {
        host: 'localhost',
        port: 8000,
        path: '/send',
        method: 'POST',
        headers: {'content-type':'application/x-www-form-urlencoded'}
  }
  
  var req = http.request(opts, (res)=>{
     res.setEncoding('utf8')
      var data = ""
      res.on('data', (d) => {
        data += d
      })
      res.on('end', ()=> {
          console.log(data);
          // 断言，不满足条件就会抛出异常
          assert.strictEqual(data, '{"status":"ok","message":"Tweet eceived"}')
      })
  });
  
  req.write('tweet=test');
  req.end();
  