Comment by slowking2

You can use tempfiles and (on OSX) use the private API of ctypes to dlclose to close the handle. Different call on Windows I think. Something like

  import _ctypes
  import shutil
  import tempfile

  @pytest.fixture
  def libfact():
      tmp = tempfile.NamedTemporaryFile(delete=True)
      shutil.copy2("./fact.so", tmp.name)
      lib = CDLL(tmp.name)
      yield lib
      _ctypes.dlclose(lib.handle)

EDIT: fixed error mentioned in reply.