Function test_map_blocks_error

xarray/tests/test_dask.py:1188–1220

(map_da, map_ds)

def test_map_blocks_error(map_da, map_ds):
    def bad_func(darray):
        return (darray * darray.x + 5 * darray.y)[:1, :1]

    with pytest.raises(ValueError, match=r"Received dimension 'x' of length 1"):
        xr.map_blocks(bad_func, map_da).compute()

    def returns_numpy(darray):
        return (darray * darray.x + 5 * darray.y).values

    with pytest.raises(TypeError, match=r"Function must return an xarray DataArray"):
        xr.map_blocks(returns_numpy, map_da)

    with pytest.raises(TypeError, match=r"args must be"):
        xr.map_blocks(operator.add, map_da, args=10)  # type: ignore[arg-type]

    with pytest.raises(TypeError, match=r"kwargs must be"):
        xr.map_blocks(operator.add, map_da, args=[10], kwargs=[20])  # type: ignore[arg-type]

    def really_bad_func(darray):
        raise ValueError("couldn't do anything.")

    with pytest.raises(Exception, match=r"Cannot infer"):
        xr.map_blocks(really_bad_func, map_da)

    ds_copy = map_ds.copy()
    ds_copy["cxy"] = ds_copy.cxy.chunk({"y": 10})

    with pytest.raises(ValueError, match=r"inconsistent chunks"):
        xr.map_blocks(bad_func, ds_copy)

    with pytest.raises(TypeError, match=r"Cannot pass dask collections"):
        xr.map_blocks(bad_func, map_da, kwargs=dict(a=map_da.chunk()))


@pytest.mark.parametrize("obj", [make_da(), make_ds()])