**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
it('should support cancel', function (done) {
    var source = axios.CancelToken.source();
    server = http.createServer(function (req, res) {
      // 
      source.cancel('Operation has been canceled.');
    }).listen(4444, function () {
      axios.get('http://localhost:4444/', {
        cancelToken: source.token
      }).catch(function (thrown) {
        assert.ok(thrown instanceof axios.Cancel, 'Promise must be rejected with a Cancel obejct');
        assert.equal(thrown.message, 'Operation has been canceled.');
        done();
      });
    });
  });
  it('should combine baseURL and url', function (done) {
    server = http.createServer(function (req, res) {
      res.end();
    }).listen(4444, function () {
      axios.get('/foo', {
        baseURL: 'http://localhost:4444/',
      }).then(function (res) {
        assert.equal(res.config.baseURL, 'http://localhost:4444/');
        assert.equal(res.config.url, '/foo');
        done();
      });
    });
  });
});