cpython/Lib/test/test_long.py

140 lines
4.4 KiB
Python

from test_support import TestFailed, verbose
from string import join
from random import random, randint
# SHIFT should match the value in longintrepr.h for best testing.
SHIFT = 15
BASE = 2 ** SHIFT
MASK = BASE - 1
# Max number of base BASE digits to use in test cases. Doubling
# this will at least quadruple the runtime.
MAXDIGITS = 10
# ------------------------------------------------------------ utilities
# Use check instead of assert so the test still does something
# under -O.
def check(ok, *args):
if not ok:
raise TestFailed, join(map(str, args), " ")
# Get random long consisting of ndigits random digits (relative to base
# BASE). The sign bit is also random.
def getran(ndigits):
answer = 0L
for i in range(ndigits):
answer = (answer << SHIFT) | randint(0, MASK)
if random() < 0.5:
answer = -answer
return answer
# --------------------------------------------------------------- divmod
def test_division_2(x, y):
q, r = divmod(x, y)
q2, r2 = x/y, x%y
check(q == q2, "divmod returns different quotient than / for", x, y)
check(r == r2, "divmod returns different mod than % for", x, y)
check(x == q*y + r, "x != q*y + r after divmod on", x, y)
if y > 0:
check(0 <= r < y, "bad mod from divmod on", x, y)
else:
check(y < r <= 0, "bad mod from divmod on", x, y)
def test_division(maxdigits=MAXDIGITS):
print "long / * % divmod"
digits = range(1, maxdigits+1)
for lenx in digits:
x = getran(lenx)
for leny in digits:
y = getran(leny) or 1L
test_division_2(x, y)
# -------------------------------------------------------------- ~ & | ^
def test_bitop_identities_1(x):
check(x == ~~x, "x != ~~x for", x)
check(x & x == x, "x & x != x for", x)
check(x | x == x, "x | x != x for", x)
check(x ^ x == 0, "x ^ x != 0 for", x)
check(x & ~x == 0, "x & ~x != 0 for", x)
check(x | ~x == -1, "x | ~x != -1 for", x)
check(x ^ ~x == -1, "x ^ ~x != -1 for", x)
check(-x == 1 + ~x, "-x != 1 + ~x for", x)
for s in range(2*SHIFT):
check( ((x >> s) << s) | (x & ((1L << s) - 1)) == x,
"((x >> s) << s) | (x & ((1L << s) - 1)) != x for",
x, s)
def test_bitop_identities_2(x, y):
check(x & y == ~(~x | ~y), "x & y != ~(~x | ~y) for", x, y)
check(x | y == ~(~x & ~y), "x | y != ~(~x & ~y) for", x, y)
check(x ^ y == (x | y) & ~(x & y),
"x ^ y != (x | y) & ~(x & y) for", x, y)
check(x ^ y == (x & ~y) | (~x & y),
"x ^ y == (x & ~y) | (~x & y) for", x, y)
check(x ^ y == (x | y) & (~x | ~y),
"x ^ y == (x | y) & (~x | ~y) for", x, y)
def test_bitop_identities_3(x, y, z):
check(x & (y | z) == (x & y) | (x & z),
"x & (y | z) != (x & y) | (x & z) for", x, y, z)
check(x | (y & z) == (x | y) & (x | z),
"x | (y & z) != (x | y) & (x | z) for", x, y, z)
def test_bitop_identities(maxdigits=MAXDIGITS):
print "long bit-operation identities"
digits = range(1, maxdigits+1)
for lenx in digits:
x = getran(lenx)
test_bitop_identities_1(x)
for leny in digits:
y = getran(leny)
test_bitop_identities_2(x, y)
test_bitop_identities_3(x, y, getran((lenx + leny)/2))
# ---------------------------------------------------------- hex oct str
def slow_format(x, base):
if (x, base) == (0, 8):
# this is an oddball!
return "0L"
digits = []
sign = 0
if x < 0:
sign, x = 1, -x
marks = "0123456789ABCDEF"
while x:
x, r = divmod(x, base)
digits.append(int(r))
digits.reverse()
digits = digits or [0]
return ['', '-'][sign] + \
{8: '0', 10: '', 16: '0x'}[base] + \
join(map(lambda i, marks=marks: marks[i], digits), '') + \
"L"
def test_format_1(x):
for base, mapper in (8, oct), (10, str), (16, hex):
got = mapper(x)
expected = slow_format(x, base)
check(got == expected, mapper.__name__, "returned",
got, "but expected", expected, "for", x)
def test_format(maxdigits=MAXDIGITS):
print "long str/hex/oct"
for i in range(10):
for lenx in range(1, maxdigits+1):
x = getran(lenx)
test_format_1(x)
# ---------------------------------------------------------------- do it
test_division()
test_bitop_identities()
test_format()