def METHOD_NAME(self):
    rfs = self.repoPrx.file(self.repo_filename, "rw")
    assert rfs.size() == 0
    wbytes = b"0123456789"
    rfs.write(wbytes, 0, len(wbytes))
    assert rfs.size() == len(wbytes)
    assert rfs.truncate(0)
    assert rfs.size() == 0