nock('http://test.com')
  .replyDate()
  .defaultReplyHeaders({
    'Content-Type': 'application/text',
    'Content-Length': function(req, res, body) { return body.length; },
  })
  .get('/testFile.txt')
  .reply(200, Buffer.from(new Array(10000).fill('a')));

http.request({
  method: 'GET',
  url: 'http://test.com/testFile.txt'
  host: 'test.com',
  path: '/testFile.txt'
}, function(response) {
  const data = []
  response.on('data', function(chunk) { data.push(chunk); });
  response.on('end', function() {
    if (!response.complete) {
      console.log('Connection terminated while the message was being sent');  // <-- The case with nock
    } else {
      console.log('Entire message received');
    }
  });
});