def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def setUp(self):
        entry_Li = ComputedEntry("Li", -1.90753119)

        with open(os.path.join(PymatgenTest.TEST_FILES_DIR, "LiTiO2_batt.json")) as f:
            entries_LTO = json.load(f, cls=MontyDecoder)
            self.ie_LTO = InsertionElectrode.from_entries(entries_LTO, entry_Li)

        with open(os.path.join(PymatgenTest.TEST_FILES_DIR, "FeF3_batt.json")) as fid:
            entries = json.load(fid, cls=MontyDecoder)
            self.ce_FF = ConversionElectrode.from_composition_and_entries(Composition("FeF3"), entries)