**Describe the bug**
Unit test case failed :
  1) supports http with nodejs
       should pass errors for a failed stream:
     Error: Timeout of 30000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (***************...

**To Reproduce**
Use VS Code internal terminal to excute the unit test .

**Expected behavior**
UT should be excuted correctly.

**Environment:**
 - Axios Version: latest master
 - OS Version: Window 10

**Additional context/Screenshots**
![Capture](https://user-images.githubusercontent.com/46782518/70436361-136c5380-1ac4-11ea-87b5-203b2e46ebbf.PNG)

test/unit/adapters/http.js
done();
        });
      });
    });
  });
  it('should support HTTP proxy auth', function (done) {
    server = http.createServer(function (req, res) {
      res.end();
    }).listen(4444, function () {
      proxy = http.createServer(function (request, response) {
        var parsed = url.parse(request.url);
        var opts = {
          host: parsed.hostname,
          port: parsed.port,
          path: parsed.path
        };
        var proxyAuth = request.headers['proxy-authorization'];
        http.get(opts, function (res) {
          var body = '';
          res.on('data', function (data) {
            body += data;
          });
          res.on('end', function () {
            response.setHeader('Content-Type', 'text/html; charset=UTF-8');
            response.end(proxyAuth);
          });
        });
      }).listen(4000, function () {
        axios.get('http://localhost:4444/', {
          proxy: {