'``LabelledFilesystem`` can be mounted.'

def test_success(self):

    filename = random_name(self)
    filecontent = random_name(self)
    with temporary_mount(LabelledFilesystem(label=self.label)) as mountpoint:
        mountpoint.child(filename).setContent(filecontent)
    with temporary_mount(LabelledFilesystem(label=self.label)) as mountpoint:
        self.assertEqual(filecontent, mountpoint.child(filename).getContent())
