'L{amp.Float.toString} raises L{ValueError} if passed an object which
is not a L{float}.'

def test_nonFloat(self):

    argument = amp.Float()
    self.assertRaises(ValueError, argument.toString, u'1.234')
    self.assertRaises(ValueError, argument.toString, '1.234')
    self.assertRaises(ValueError, argument.toString, 1234)
