import unittest
import os
from selenium import webdriver

class TestAutoMethods(unittest.TestCase):
    #打开Firefox浏览器
    def test_openbrower(self):
       browser = webdriver.Firefox()
       browser.get("http://www.baidu.com")

    def test_FirstVase(self):
        #ie_driver = os.path.abspath(r"C:\Program Files(x86)\Internet Explorer\IEDriverServer.exe")
        #os.environ["webdriver.ie.driver"] = ie_driver
        browser = webdriver.Ie()
        browser.get("http://www.youdao.com")

if __name__ == '__main__':
    unittest.main()

Error
Traceback (most recent call last):
  File "D:\Users\chenle\PycharmProjects\untitled\test\FirstExam.py", line 14, in test_FirstVase
    browser = webdriver.Ie()
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\ie\webdriver.py", line 57, in __init__
    desired_capabilities=capabilities)
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 92, in __init__
    self.start_session(desired_capabilities, browser_profile)
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 179, in start_session
    response = self.execute(Command.NEW_SESSION, capabilities)
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 234, in execute
    response = self.command_executor.execute(driver_command, params)
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\remote\remote_connection.py", line 408, in execute
    return self._request(command_info[0], url, body=data)
  File "C:\Program Files\Python36\lib\site-packages\selenium\webdriver\remote\remote_connection.py", line 478, in _request
    resp = opener.open(request, timeout=self._timeout)
  File "C:\Program Files\Python36\lib\urllib\request.py", line 526, in open
    response = self._open(req, data)
  File "C:\Program Files\Python36\lib\urllib\request.py", line 544, in _open
    '_open', req)
  File "C:\Program Files\Python36\lib\urllib\request.py", line 504, in _call_chain
    result = func(*args)
  File "C:\Program Files\Python36\lib\urllib\request.py", line 1346, in http_open
    return self.do_open(http.client.HTTPConnection, req)
  File "C:\Program Files\Python36\lib\urllib\request.py", line 1321, in do_open
    r = h.getresponse()
  File "C:\Program Files\Python36\lib\http\client.py", line 1331, in getresponse
    response.begin()
  File "C:\Program Files\Python36\lib\http\client.py", line 297, in begin
    version, status, reason = self._read_status()
  File "C:\Program Files\Python36\lib\http\client.py", line 266, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response