def to_classname(filename: str) -> str:
    """
    maps divided mock class file name to class names
    inverse function of headersplit.to_filename
    e.g. map "test/mocks/server/admin_stream.h" to "MockAdminStream"

    Args:
        filename: string, mock class header file name (might be the whole path instead of the base name)

    Returns:
        corresponding class name
    """
    classname_tokens = filename.split('/')[-1].replace('.h', '').split('_')
    classname = "Mock" + ''.join(map(lambda x: x[:1].upper() + x[1:], classname_tokens))
    return classname