Function test_range_index_empty_slice

xarray/tests/test_range_index.py:169–222

Test that empty slices of RangeIndex are printable and preserve step. Regression test for https://github.com/pydata/xarray/issues/10547

()

def test_range_index_empty_slice() -> None:
    """Test that empty slices of RangeIndex are printable and preserve step.

    Regression test for https://github.com/pydata/xarray/issues/10547
    """
    # Test with linspace
    n = 30
    step = 1
    da = xr.DataArray(np.zeros(n), dims=["x"])
    da = da.assign_coords(
        xr.Coordinates.from_xindex(RangeIndex.linspace(0, (n - 1) * step, n, dim="x"))
    )

    # This should not raise ZeroDivisionError
    sub = da.isel(x=slice(0))
    assert sub.sizes["x"] == 0

    # Test that it's printable
    repr_str = repr(sub)
    assert "RangeIndex" in repr_str
    assert "step=1" in repr_str

    # Test with different step values
    index = RangeIndex.arange(0, 10, 2.5, dim="y")
    da2 = xr.DataArray(np.zeros(4), dims=["y"])
    da2 = da2.assign_coords(xr.Coordinates.from_xindex(index))
    empty = da2.isel(y=slice(0))

    # Should preserve step
    assert empty.sizes["y"] == 0
    range_index_y = empty._indexes["y"]
    assert isinstance(range_index_y, RangeIndex)
    assert range_index_y.step == 2.5

    # Test that it's printable
    repr_str2 = repr(empty)
    assert "RangeIndex" in repr_str2
    assert "step=2.5" in repr_str2

    # Test negative step
    index3 = RangeIndex.arange(10, 0, -1, dim="z")
    da3 = xr.DataArray(np.zeros(10), dims=["z"])
    da3 = da3.assign_coords(xr.Coordinates.from_xindex(index3))
    empty3 = da3.isel(z=slice(0))

    assert empty3.sizes["z"] == 0
    range_index_z = empty3._indexes["z"]
    assert isinstance(range_index_z, RangeIndex)
    assert range_index_z.step == -1.0

    # Test that it's printable
    repr_str3 = repr(empty3)
    assert "RangeIndex" in repr_str3
    assert "step=-1" in repr_str3


def test_range_index_sel() -> None: