Function test_to_backend

dask/dataframe/tests/test_dataframe.py:5118–5130

()

def test_to_backend():
    # Test that `DataFrame.to_backend` works as expected
    with dask.config.set({"dataframe.backend": "pandas"}):
        # Start with pandas-backed data
        df = dd.from_dict({"a": range(10)}, npartitions=2)
        assert isinstance(df._meta, pd.DataFrame)

        # Default `to_backend` shouldn't change data
        assert_eq(df, df.to_backend())

        # Moving to a "missing" backend should raise an error
        with pytest.raises(ValueError, match="No backend dispatch registered"):
            df.to_backend("missing")


@pytest.mark.parametrize("func", ["max", "sum"])