use pwd not os for getting login

CI os.getlogin() doesn't work

    def test_docker_user_setting(self):
>       self.assertEqual(os.getlogin(), get_user_name())
E       OSError: [Errno 6] No such device or address

test/test_core.py

@@ -18,6 +18,7 @@
 import argparse
 import em
 import os
+import pwd
 import pytest
 import unittest
 
@@ -150,9 +151,12 @@ def test_docker_cmd_interactive(self):
 
  self.assertNotIn('-it', dig.generate_docker_cmd(mode='non-interactive'))
 
+ def test_docker_user_detection(self):
+ userinfo = pwd.getpwuid(os.getuid())
+ username_detected = getattr(userinfo, 'pw_' + 'name')
+ self.assertEqual(username_detected, get_user_name())
 
  def test_docker_user_setting(self):
- self.assertEqual(os.getlogin(), get_user_name())
  parser = argparse.ArgumentParser()
  extension_manager = RockerExtensionManager()
  default_args = {}