diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/test/test_math.py | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py index 5c35c8c..b64fd41 100644 --- a/Lib/test/test_math.py +++ b/Lib/test/test_math.py @@ -2033,6 +2033,60 @@ class IsCloseTests(unittest.TestCase): self.assertIs(type(comb(IntSubclass(5), IntSubclass(k))), int) self.assertIs(type(comb(MyIndexable(5), MyIndexable(k))), int) + def assertEqualSign(self, x, y): + """Similar to assertEqual(), but compare also the sign. + + Function useful to check to signed zero. + """ + self.assertEqual(x, y) + self.assertEqual(math.copysign(1.0, x), math.copysign(1.0, y)) + + @requires_IEEE_754 + def test_nextafter(self): + # around 2^52 and 2^63 + self.assertEqual(math.nextafter(4503599627370496.0, -INF), + 4503599627370495.5) + self.assertEqual(math.nextafter(4503599627370496.0, INF), + 4503599627370497.0) + self.assertEqual(math.nextafter(9223372036854775808.0, 0.0), + 9223372036854774784.0) + self.assertEqual(math.nextafter(-9223372036854775808.0, 0.0), + -9223372036854774784.0) + + # around 1.0 + self.assertEqual(math.nextafter(1.0, -INF), + float.fromhex('0x1.fffffffffffffp-1')) + self.assertEqual(math.nextafter(1.0, INF), + float.fromhex('0x1.0000000000001p+0')) + + # x == y: y is returned + self.assertEqual(math.nextafter(2.0, 2.0), 2.0) + self.assertEqualSign(math.nextafter(-0.0, +0.0), +0.0) + self.assertEqualSign(math.nextafter(+0.0, -0.0), -0.0) + + # around 0.0 + smallest_subnormal = sys.float_info.min * sys.float_info.epsilon + self.assertEqual(math.nextafter(+0.0, INF), smallest_subnormal) + self.assertEqual(math.nextafter(-0.0, INF), smallest_subnormal) + self.assertEqual(math.nextafter(+0.0, -INF), -smallest_subnormal) + self.assertEqual(math.nextafter(-0.0, -INF), -smallest_subnormal) + self.assertEqualSign(math.nextafter(smallest_subnormal, +0.0), +0.0) + self.assertEqualSign(math.nextafter(-smallest_subnormal, +0.0), -0.0) + self.assertEqualSign(math.nextafter(smallest_subnormal, -0.0), +0.0) + self.assertEqualSign(math.nextafter(-smallest_subnormal, -0.0), -0.0) + + # around infinity + largest_normal = sys.float_info.max + self.assertEqual(math.nextafter(INF, 0.0), largest_normal) + self.assertEqual(math.nextafter(-INF, 0.0), -largest_normal) + self.assertEqual(math.nextafter(largest_normal, INF), INF) + self.assertEqual(math.nextafter(-largest_normal, -INF), -INF) + + # NaN + self.assertTrue(math.isnan(math.nextafter(NAN, 1.0))) + self.assertTrue(math.isnan(math.nextafter(1.0, NAN))) + self.assertTrue(math.isnan(math.nextafter(NAN, NAN))) + def test_main(): from doctest import DocFileSuite |