Function env_modify

test/common.py:164–181

A context manager that updates os.environ.

(updates)

@contextlib.contextmanager
def env_modify(updates):
  """A context manager that updates os.environ."""
  # This could also be done with mock.patch.dict() but taking a dependency
  # on the mock library is probably not worth the benefit.
  old_env = os.environ.copy()
  print("env_modify: " + str(updates))
  # Setting a value to None means clear the environment variable
  clears = [key for key, value in updates.items() if value is None]
  updates = {key: value for key, value in updates.items() if value is not None}
  os.environ.update(updates)
  for key in clears:
    if key in os.environ:
      del os.environ[key]
  try:
    yield
  finally:
    os.environ.clear()
    os.environ.update(old_env)


def ensure_dir(dirname):