def test_open_mfdataset_list_attr() -> None:
    """
    Case when an attribute of type list differs across the multiple files
    """
    from netCDF4 import Dataset

    with create_tmp_files(2) as nfiles:
        for i in range(2):
            with Dataset(nfiles[i], "w") as f:
                f.createDimension("x", 3)
                vlvar = f.createVariable("test_var", np.int32, ("x"))
                # here create an attribute as a list
                vlvar.test_attr = [f"string a {i}", f"string b {i}"]
                vlvar[:] = np.arange(3)

        with open_dataset(nfiles[0]) as ds1:
            with open_dataset(nfiles[1]) as ds2:
                original = xr.concat([ds1, ds2], dim="x")
                with xr.open_mfdataset(
                    [nfiles[0], nfiles[1]], combine="nested", concat_dim="x"
                ) as actual:
                    assert_identical(actual, original)

    Case when an attribute of type list differs across the multiple files
    
xarray/tests/test_backends.py