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Reduce number of random tests in test_strtod, to avoid hogging buildbot time.

This commit is contained in:
Mark Dickinson 2010-02-21 14:42:27 +00:00
parent 45ad801ed0
commit 92cb4a8c6f
1 changed files with 27 additions and 33 deletions
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60
Lib/test/test_strtod.py
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@ -80,7 +80,7 @@ def strtod(s, mant_dig=53, min_exp = -1021, max_exp = 1024):
hexdigs, hexdigs,
e + 4*hexdigs) e + 4*hexdigs)
TEST_SIZE = 16 TEST_SIZE = 10
class StrtodTests(unittest.TestCase): class StrtodTests(unittest.TestCase):
def check_strtod(self, s): def check_strtod(self, s):
@ -111,7 +111,7 @@ class StrtodTests(unittest.TestCase):
lower = -(-2**53//5**k) lower = -(-2**53//5**k)
if lower % 2 == 0: if lower % 2 == 0:
lower += 1 lower += 1
for i in xrange(10 * TEST_SIZE): for i in xrange(TEST_SIZE):
# Select a random odd n in [2**53/5**k, # Select a random odd n in [2**53/5**k,
# 2**54/5**k). Then n * 10**k gives a halfway case # 2**54/5**k). Then n * 10**k gives a halfway case
# with small number of significant digits. # with small number of significant digits.
@ -147,34 +147,29 @@ class StrtodTests(unittest.TestCase):
def test_halfway_cases(self): def test_halfway_cases(self):
# test halfway cases for the round-half-to-even rule # test halfway cases for the round-half-to-even rule
for i in xrange(1000): for i in xrange(100 * TEST_SIZE):
for j in xrange(TEST_SIZE): # bit pattern for a random finite positive (or +0.0) float
# bit pattern for a random finite positive (or +0.0) float bits = random.randrange(2047*2**52)
bits = random.randrange(2047*2**52)
# convert bit pattern to a number of the form m * 2**e # convert bit pattern to a number of the form m * 2**e
e, m = divmod(bits, 2**52) e, m = divmod(bits, 2**52)
if e: if e:
m, e = m + 2**52, e - 1 m, e = m + 2**52, e - 1
e -= 1074 e -= 1074
# add 0.5 ulps # add 0.5 ulps
m, e = 2*m + 1, e - 1 m, e = 2*m + 1, e - 1
# convert to a decimal string # convert to a decimal string
if e >= 0: if e >= 0:
digits = m << e digits = m << e
exponent = 0 exponent = 0
else: else:
# m * 2**e = (m * 5**-e) * 10**e # m * 2**e = (m * 5**-e) * 10**e
digits = m * 5**-e digits = m * 5**-e
exponent = e exponent = e
s = '{}e{}'.format(digits, exponent) s = '{}e{}'.format(digits, exponent)
self.check_strtod(s) self.check_strtod(s)
# get expected answer via struct, to triple check
#fs = struct.unpack('<d', struct.pack('<Q', bits + (bits&1)))[0]
#self.assertEqual(fs, float(s))
def test_boundaries(self): def test_boundaries(self):
# boundaries expressed as triples (n, e, u), where # boundaries expressed as triples (n, e, u), where
@ -188,11 +183,10 @@ class StrtodTests(unittest.TestCase):
] ]
for n, e, u in boundaries: for n, e, u in boundaries:
for j in xrange(1000): for j in xrange(1000):
for i in xrange(TEST_SIZE): digits = n + random.randrange(-3*u, 3*u)
digits = n + random.randrange(-3*u, 3*u) exponent = e
exponent = e s = '{}e{}'.format(digits, exponent)
s = '{}e{}'.format(digits, exponent) self.check_strtod(s)
self.check_strtod(s)
n *= 10 n *= 10
u *= 10 u *= 10
e -= 1 e -= 1
@ -211,7 +205,7 @@ class StrtodTests(unittest.TestCase):
def test_bigcomp(self): def test_bigcomp(self):
for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50: for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50:
dig10 = 10**ndigs dig10 = 10**ndigs
for i in xrange(100 * TEST_SIZE): for i in xrange(10 * TEST_SIZE):
digits = random.randrange(dig10) digits = random.randrange(dig10)
exponent = random.randrange(-400, 400) exponent = random.randrange(-400, 400)
s = '{}e{}'.format(digits, exponent) s = '{}e{}'.format(digits, exponent)