change env variable for using EnvironmentVarGuard

environment_var_guard.py

import unittest
from test.support import EnvironmentVarGuard

class TestConnection(unittest.TestCase):
    pass

if __name__ == "__main__":
    env = EnvironmentVarGuard()
    env.set('DEVELOP_USER', 'test_user')
    env.set('DEVELOP_PASSWORD', 'test_password')
    with env:
        unittest.main()