**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
.then(function (resp) {
          assert.equal(resp.status, 200);
          assert.equal(resp.statusText, 'OK');
          done();
        })
        .catch(function (error) {
          assert.ifError(error);
          done();
        });
    });
  });
  it('should support streams', function (done) {
    server = http.createServer(function (req, res) {
      req.pipe(res);
    }).listen(4444, function () {
      axios.post('http://localhost:4444/',
        fs.createReadStream(__filename), {
          responseType: 'stream'
        }).then(function (res) {
          var stream = res.data;
          var string = '';
          stream.on('data', function (chunk) {
            string += chunk.toString('utf8');
          });
          stream.on('end', function () {
            assert.equal(string, fs.readFileSync(__filename, 'utf8'));
            done();
          });
        });
    });