def test_multi_device_default_strategy():
    """The default strategy when multiple devices are selected is "ddp" with the subprocess launcher."""
    connector = _Connector(strategy="auto", accelerator="cpu", devices=2)
    assert isinstance(connector.accelerator, CPUAccelerator)
    assert isinstance(connector.strategy, DDPStrategy)
    assert connector.strategy._start_method == "popen"
    assert isinstance(connector.strategy.launcher, _SubprocessScriptLauncher)
The default strategy when multiple devices are selected is "ddp" with the subprocess launcher.
tests/tests_fabric/test_connector.py