test_decimal.py 文件源码

def test_from_float(self):

        class  MyDecimal(Decimal):
            pass

        r = MyDecimal.from_float(0.1)
        self.assertEqual(type(r), MyDecimal)
        self.assertEqual(str(r),
                '0.1000000000000000055511151231257827021181583404541015625')
        bigint = 12345678901234567890123456789
        self.assertEqual(MyDecimal.from_float(bigint), MyDecimal(bigint))
        self.assertTrue(MyDecimal.from_float(float('nan')).is_qnan())
        self.assertTrue(MyDecimal.from_float(float('inf')).is_infinite())
        self.assertTrue(MyDecimal.from_float(float('-inf')).is_infinite())
        self.assertEqual(str(MyDecimal.from_float(float('nan'))),
                         str(Decimal('NaN')))
        self.assertEqual(str(MyDecimal.from_float(float('inf'))),
                         str(Decimal('Infinity')))
        self.assertEqual(str(MyDecimal.from_float(float('-inf'))),
                         str(Decimal('-Infinity')))
        self.assertRaises(TypeError, MyDecimal.from_float, 'abc')
        for i in range(200):
            x = random.expovariate(0.01) * (random.random() * 2.0 - 1.0)
            self.assertEqual(x, float(MyDecimal.from_float(x))) # roundtrip