def get_test_info(test_file):
    """Obtains information about gninatypes file.

    Arguments:
        test_file: text file containing labels and paths to gninatypes files

    Returns:
        dictionary containing tuples with the format:
            {index : (receptor_path, ligand_path)}
            where index is the line number, receptor_path is the path to the
            receptor gninatype and ligand_path is the path to the ligand
            gninatype.
    """
    paths = {}
    with open(test_file, 'r') as f:
        for idx, line in enumerate(f.readlines()):
            chunks = line.strip().split()
            paths[idx] = (chunks[-2], chunks[-1])
    return paths, len(paths)