def isascii(text):
    """Test if ``text`` contains only ASCII characters.

    :param text: text to test for ASCII-ness
    :type text: ``unicode``
    :returns: ``True`` if ``text`` contains only ASCII characters
    :rtype: ``Boolean``

    """
    try:
        text.encode('ascii')
    except UnicodeEncodeError:
        return False
    return True
