diff options
Diffstat (limited to 'Lib/test/test_strtod.py')
| -rw-r--r-- | Lib/test/test_strtod.py | 99 |
1 files changed, 95 insertions, 4 deletions
diff --git a/Lib/test/test_strtod.py b/Lib/test/test_strtod.py index 7830021ee8..13b008be1a 100644 --- a/Lib/test/test_strtod.py +++ b/Lib/test/test_strtod.py @@ -100,6 +100,49 @@ class StrtodTests(unittest.TestCase): "Incorrectly rounded str->float conversion for {}: " "expected {}, got {}".format(s, expected, got)) + def test_short_halfway_cases(self): + # exact halfway cases with a small number of significant digits + for k in 0, 5, 10, 15, 20: + # upper = smallest integer >= 2**54/5**k + upper = -(-2**54//5**k) + # lower = smallest odd number >= 2**53/5**k + lower = -(-2**53//5**k) + if lower % 2 == 0: + lower += 1 + for i in range(10 * TEST_SIZE): + # Select a random odd n in [2**53/5**k, + # 2**54/5**k). Then n * 10**k gives a halfway case + # with small number of significant digits. + n, e = random.randrange(lower, upper, 2), k + + # Remove any additional powers of 5. + while n % 5 == 0: + n, e = n // 5, e + 1 + assert n % 10 in (1, 3, 7, 9) + + # Try numbers of the form n * 2**p2 * 10**e, p2 >= 0, + # until n * 2**p2 has more than 20 significant digits. + digits, exponent = n, e + while digits < 10**20: + s = '{}e{}'.format(digits, exponent) + self.check_strtod(s) + # Same again, but with extra trailing zeros. + s = '{}e{}'.format(digits * 10**40, exponent - 40) + self.check_strtod(s) + digits *= 2 + + # Try numbers of the form n * 5**p2 * 10**(e - p5), p5 + # >= 0, with n * 5**p5 < 10**20. + digits, exponent = n, e + while digits < 10**20: + s = '{}e{}'.format(digits, exponent) + self.check_strtod(s) + # Same again, but with extra trailing zeros. + s = '{}e{}'.format(digits * 10**40, exponent - 40) + self.check_strtod(s) + digits *= 5 + exponent -= 1 + def test_halfway_cases(self): # test halfway cases for the round-half-to-even rule for i in range(1000): @@ -164,10 +207,10 @@ class StrtodTests(unittest.TestCase): self.check_strtod(s) def test_bigcomp(self): - DIG10 = 10**50 - for i in range(1000): - for j in range(TEST_SIZE): - digits = random.randrange(DIG10) + for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50: + dig10 = 10**ndigs + for i in range(100 * TEST_SIZE): + digits = random.randrange(dig10) exponent = random.randrange(-400, 400) s = '{}e{}'.format(digits, exponent) self.check_strtod(s) @@ -254,11 +297,59 @@ class StrtodTests(unittest.TestCase): # demonstration that original fix for issue 7632 bug 1 was # buggy; the exit condition was too strong '247032822920623295e-341', + # demonstrate similar problem to issue 7632 bug1: crash + # with 'oversized quotient in quorem' message. + '99037485700245683102805043437346965248029601286431e-373', + '99617639833743863161109961162881027406769510558457e-373', + '98852915025769345295749278351563179840130565591462e-372', + '99059944827693569659153042769690930905148015876788e-373', + '98914979205069368270421829889078356254059760327101e-372', # issue 7632 bug 5: the following 2 strings convert differently '1000000000000000000000000000000000000000e-16', '10000000000000000000000000000000000000000e-17', + # issue 7632 bug 7 + '991633793189150720000000000000000000000000000000000000000e-33', + # And another, similar, failing halfway case + '4106250198039490000000000000000000000000000000000000000e-38', # issue 7632 bug 8: the following produced 10.0 '10.900000000000000012345678912345678912345', + # exercise exit conditions in bigcomp comparison loop + '2602129298404963083833853479113577253105939995688e2', + '260212929840496308383385347911357725310593999568896e0', + '26021292984049630838338534791135772531059399956889601e-2', + '260212929840496308383385347911357725310593999568895e0', + '260212929840496308383385347911357725310593999568897e0', + '260212929840496308383385347911357725310593999568996e0', + '260212929840496308383385347911357725310593999568866e0', + # 2**53 + '9007199254740992.00', + # 2**1024 - 2**970: exact overflow boundary. All values + # smaller than this should round to something finite; any value + # greater than or equal to this one overflows. + '179769313486231580793728971405303415079934132710037' #... + '826936173778980444968292764750946649017977587207096' #... + '330286416692887910946555547851940402630657488671505' #... + '820681908902000708383676273854845817711531764475730' #... + '270069855571366959622842914819860834936475292719074' #... + '168444365510704342711559699508093042880177904174497792', + # 2**1024 - 2**970 - tiny + '179769313486231580793728971405303415079934132710037' #... + '826936173778980444968292764750946649017977587207096' #... + '330286416692887910946555547851940402630657488671505' #... + '820681908902000708383676273854845817711531764475730' #... + '270069855571366959622842914819860834936475292719074' #... + '168444365510704342711559699508093042880177904174497791.999', + # 2**1024 - 2**970 + tiny + '179769313486231580793728971405303415079934132710037' #... + '826936173778980444968292764750946649017977587207096' #... + '330286416692887910946555547851940402630657488671505' #... + '820681908902000708383676273854845817711531764475730' #... + '270069855571366959622842914819860834936475292719074' #... + '168444365510704342711559699508093042880177904174497792.001', + # 1 - 2**-54, +-tiny + '999999999999999944488848768742172978818416595458984375e-54', + '9999999999999999444888487687421729788184165954589843749999999e-54', + '9999999999999999444888487687421729788184165954589843750000001e-54', ] for s in test_strings: self.check_strtod(s) |