Create a unique temporary dir:
python
def test_whatever(self):
    tmp_dir = self.get_auto_remove_tmp_dir()
tmp_dir will contain the path to the created temporary dir. It will be automatically removed at the end of the
test.
Create a temporary dir of my choice, ensure it's empty before the test starts and don't empty it after the test.
python
def test_whatever(self):
    tmp_dir = self.get_auto_remove_tmp_dir("./xxx")
This is useful for debug when you want to monitor a specific directory and want to make sure the previous tests didn't
leave any data in there.
You can override the default behavior by directly overriding the before and after args, leading to one of the
  following behaviors:
before=True: the temporary dir will always be cleared at the beginning of the test.
before=False: if the temporary dir already existed, any existing files will remain there.
