'L{ListOf.fromBox} reverses the operation performed by L{ListOf.toBox}.'

def test_fromBox(self):

    def is_qnan(decimal):
        return (('NaN' in str(decimal)) and ('sNaN' not in str(decimal)))
    def is_snan(decimal):
        return ('sNaN' in str(decimal))
    def is_signed(decimal):
        return ('-' in str(decimal))
    stringList = amp.ListOf(self.elementType)
    objects = {}
    for key in self.strings:
        stringList.fromBox(key, self.strings.copy(), objects, None)
    n = objects['nan']
    self.assertTrue((is_qnan(n[0]) and (not is_signed(n[0]))))
    self.assertTrue((is_qnan(n[1]) and is_signed(n[1])))
    self.assertTrue((is_snan(n[2]) and (not is_signed(n[2]))))
    self.assertTrue((is_snan(n[3]) and is_signed(n[3])))
