def METHOD_NAME(monkeypatch, tmpdir):
    partfile = os.path.join(tmpdir, "fake-partition")
    find_unused = mock.Mock()
    monkeypatch.setattr(common.update_actions, "_find_unused_partition", find_unused)
    find_unused.return_value = FakeRootPartElem(
        "TWO", common.update_actions.Partition(2, partfile)
    )
    return partfile