[Tutor] Patching os.environ

[Albert-Jan Roskam]

   Hi,
   What is the correct way of patching a dict in a test fixture? Below,
   MyTest1 fails, while MyTest2 succeeds. I thought the two tests were
   equivalent!
   Thanks!
   Albert-Jan
   import os
   import unittest
   from unittest.mock import patch
   class MyTest1(unittest.TestCase):
       def setUp(self):
           patcher = patch.dict(os.environ, {"FOO": "bar"}, clear=True)
           self.addCleanup(patcher.stop)
       def test_bla1(self):
           # why does this test fail?
           self.assertEqual(os.environ.get("FOO"), "bar")
   class MyTest2(unittest.TestCase):
       @patch.dict(os.environ, {"FOO": "bar"}, clear=True)
       def test_bla2(self):
           self.assertEqual(os.environ.get("FOO"), "bar")
   if __name__ == "__main__":
       unittest.main()