Repository: Lightning-AI/pytorch-lightning
File: tests/tests_fabric/plugins/environments/test_xla.py (Python)

Code before:
    with pytest.raises(NotImplementedError):
        _ = env.main_port
    assert env.world_size() == 2
    assert env.global_rank() == 0
    assert env.local_rank() == 2
    assert env.node_rank() == 1
    env.set_global_rank(100)
    assert env.global_rank() == 0
    env.set_world_size(100)
    assert env.world_size() == 2


def test_detect(monkeypatch):
    """Test the detection of a xla environment configuration."""
    monkeypatch.setattr(lightning.fabric.accelerators.xla.XLAAccelerator, "is_available", lambda: False)
    assert not XLAEnvironment.detect()

    monkeypatch.setattr(lightning.fabric.accelerators.xla.XLAAccelerator, "is_available", lambda: True)
    assert XLAEnvironment.detect()


@mock.patch.dict(os.environ, {}, clear=True)
def test_attributes_from_xla_greater_21_used(xla_available, monkeypatch):
    """Test XLA environment attributes when using XLA runtime >= 2.1."""
    monkeypatch.setattr(lightning.fabric.accelerators.xla, "_XLA_GREATER_EQUAL_2_1", True)
    monkeypatch.setattr(lightning.fabric.plugins.environments.xla, "_XLA_GREATER_EQUAL_2_1", True)

    env = XLAEnvironment()

    with (
        mock.patch("torch_xla.runtime.world_size", return_value=4),
        mock.patch("torch_xla.runtime.global_ordinal", return_value=2),
        mock.patch("torch_xla.runtime.local_ordinal", return_value=1),
    ):
        env.world_size.cache_clear()
        env.global_rank.cache_clear()
        env.local_rank.cache_clear()

        assert env.world_size() == 4
        assert env.global_rank() == 2
        assert env.local_rank() == 1

        env.set_world_size(100)
        assert env.world_size() == 4

        env.set_global_rank(100)
        assert env.global_rank() == 2


Review comment (suggestion):
```suggestion


@mock.patch.dict(os.environ, {}, clear=True)
@mock.patch("lightning.fabric.accelerators.xla._XLA_GREATER_EQUAL_2_1", True)
@mock.patch("(lightning.fabric.plugins.environments.xla._XLA_GREATER_EQUAL_2_1", True)
def test_attributes_from_xla_greater_21_used(xla_available, monkeypatch):
    """Test XLA environment attributes when using XLA runtime >= 2.1."""
```

Code after:
    with pytest.raises(NotImplementedError):
        _ = env.main_port
    assert env.world_size() == 2
    assert env.global_rank() == 0
    assert env.local_rank() == 2
    assert env.node_rank() == 1
    env.set_global_rank(100)
    assert env.global_rank() == 0
    env.set_world_size(100)
    assert env.world_size() == 2


def test_detect(monkeypatch):
    """Test the detection of a xla environment configuration."""
    monkeypatch.setattr(lightning.fabric.accelerators.xla.XLAAccelerator, "is_available", lambda: False)
    assert not XLAEnvironment.detect()

    monkeypatch.setattr(lightning.fabric.accelerators.xla.XLAAccelerator, "is_available", lambda: True)
    assert XLAEnvironment.detect()


@mock.patch.dict(os.environ, {}, clear=True)
@mock.patch("lightning.fabric.accelerators.xla._XLA_GREATER_EQUAL_2_1", True)
@mock.patch("lightning.fabric.plugins.environments.xla._XLA_GREATER_EQUAL_2_1", True)
def test_world_size_from_xla_runtime_greater_2_1(xla_available):
    """Test that world_size uses torch_xla.runtime when XLA >= 2.1."""
    env = XLAEnvironment()

    with mock.patch("torch_xla.runtime.world_size", return_value=4) as mock_world_size:
        env.world_size.cache_clear()
        assert env.world_size() == 4
        mock_world_size.assert_called_once()


@mock.patch.dict(os.environ, {}, clear=True)
@mock.patch("lightning.fabric.accelerators.xla._XLA_GREATER_EQUAL_2_1", True)
@mock.patch("lightning.fabric.plugins.environments.xla._XLA_GREATER_EQUAL_2_1", True)
def test_global_rank_from_xla_runtime_greater_2_1(xla_available):
    """Test that global_rank uses torch_xla.runtime when XLA >= 2.1."""
    env = XLAEnvironment()

    with mock.patch("torch_xla.runtime.global_ordinal", return_value=2) as mock_global_ordinal:
        env.global_rank.cache_clear()
        assert env.global_rank() == 2
        mock_global_ordinal.assert_called_once()


@mock.patch.dict(os.environ, {}, clear=True)
@mock.patch("lightning.fabric.accelerators.xla._XLA_GREATER_EQUAL_2_1", True)
@mock.patch("lightning.fabric.plugins.environments.xla._XLA_GREATER_EQUAL_2_1", True)
def test_local_rank_from_xla_runtime_greater_2_1(xla_available):