def group(text, size):
    """Group ``text`` into blocks of ``size``.

    Example:
        >>> group("test", 2)
        ['te', 'st']

    Args:
        text (str): text to separate
        size (int): size of groups to split the text into

    Returns:
        List of n-sized groups of text

    Raises:
        ValueError: If n is non positive
    """
    if size <= 0:
        raise ValueError("n must be a positive integer")

    return [text[i:i + size] for i in range(0, len(text), size)]