code: def test_username_takes_username_from_env(self, environ):
      expected_name = "some_name"
      environ.get.return_value = expected_name
      self.assertEqual(expected_name, getpass.getuser())
  
imports: import getpass
  import os
  import unittest
  from io import BytesIO, StringIO, TextIOWrapper
  from unittest import mock
  from test import support
label_desc: Use image node_id 1 for calling the GetpassGetuserTest obj's underlying member method code with example usage: obj.test_username_takes_username_from_env(environ) without return types