Fix renderer tests that relied on default ISM metadata when no -im was given

    if in_meta_files is None and in_fmt in format_to_metadata_files:

        in_meta_files = format_to_metadata_files[in_fmt]

    # If metadata not given with ISM input, use default NULL

    if in_meta_files is None and isinstance(in_fmt, str) and "ism" in in_fmt.lower():

        match = re.search(r"ism(\d)", in_fmt.lower())

        assert match is not None

        num_obj = int(match[1])

        in_meta_files = ["NULL"] * num_obj

    if out_file is None:

        out_file_stem = f"{in_name}_to_{out_name}{trj_name}{non_diegetic_pan}{refrot_name}{refvec_name}{refveclev_name}{config_name}{framing_name}{hrtf_file_name}{name_extension}{aeid_name}_{sr}.wav"

        out_file = str(output_path_base.joinpath(out_file_stem))