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authorTim Peters <tim.peters@gmail.com>2000-10-06 00:36:09 (GMT)
committerTim Peters <tim.peters@gmail.com>2000-10-06 00:36:09 (GMT)
commitc54d19043a595679f253a55e46fda2910f513c52 (patch)
treea737fd6e07e1224f22837ac9822f36b5cdb1524d /Lib/test/test_pow.py
parent4779a0a6fd444d594f1cbb992c636d66f59a5d1d (diff)
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SF bug 115831 and Ping's SF patch 101751, 0.0**-2.0 returns inf rather than
raise ValueError. Checked in the patch as far as it went, but also changed all of ints, longs and floats to raise ZeroDivisionError instead when raising 0 to a negative number. This is what 754-inspired stds require, as the "true result" is an infinity obtained from finite operands, i.e. it's a singularity. Also changed float pow to not be so timid about using its square-and-multiply algorithm. Note that what math.pow does is unrelated to what builtin pow does, and will still vary by platform.
Diffstat (limited to 'Lib/test/test_pow.py')
-rw-r--r--Lib/test/test_pow.py85
1 files changed, 55 insertions, 30 deletions
diff --git a/Lib/test/test_pow.py b/Lib/test/test_pow.py
index 6e3dda7..22c1972 100644
--- a/Lib/test/test_pow.py
+++ b/Lib/test/test_pow.py
@@ -2,44 +2,69 @@ import sys
import test_support
def powtest(type):
- if (type!=float):
+ if type != float:
print " Testing 2-argument pow() function..."
for i in range(-1000, 1000):
- if (pow(type(i),0)!=1):
+ if pow(type(i), 0) != 1:
raise ValueError, 'pow('+str(i)+',0) != 1'
- if (pow(type(i),1)!=type(i)):
+ if pow(type(i), 1) != type(i):
raise ValueError, 'pow('+str(i)+',1) != '+str(i)
- if (pow(type(0),1)!=type(0)):
+ if pow(type(0), 1) != type(0):
raise ValueError, 'pow(0,'+str(i)+') != 0'
- if (pow(type(1),1)!=type(1)):
+ if pow(type(1), 1) != type(1):
raise ValueError, 'pow(1,'+str(i)+') != 1'
-
+
for i in range(-100, 100):
- if (pow(type(i),3)!=i*i*i):
+ if pow(type(i), 3) != i*i*i:
raise ValueError, 'pow('+str(i)+',3) != '+str(i*i*i)
- pow2=1
+ pow2 = 1
for i in range(0,31):
- if (pow(2,i)!=pow2):
+ if pow(2, i) != pow2:
raise ValueError, 'pow(2,'+str(i)+') != '+str(pow2)
- if (i!=30): pow2=pow2*2
+ if i != 30 : pow2 = pow2*2
+
+ for othertype in int, long:
+ for i in range(-10, 0) + range(1, 10):
+ ii = type(i)
+ for j in range(1, 11):
+ jj = -othertype(j)
+ try:
+ pow(ii, jj)
+ except ValueError:
+ pass # taking an int to a neg int power should fail
+ else:
+ raise ValueError, "pow(%s, %s) did not fail" % (ii, jj)
+
+ for othertype in int, long, float:
+ for i in range(1, 100):
+ zero = type(0)
+ exp = -othertype(i/10.0)
+ if exp == 0:
+ continue
+ try:
+ pow(zero, exp)
+ except ZeroDivisionError:
+ pass # taking zero to any negative exponent should fail
+ else:
+ raise ValueError, "pow(%s, %s) did not fail" % (zero, exp)
print " Testing 3-argument pow() function..."
il, ih = -20, 20
jl, jh = -5, 5
kl, kh = -10, 10
compare = cmp
- if (type==float):
- il=1
+ if type == float:
+ il = 1
compare = test_support.fcmp
- elif (type==int):
- jl=0
- elif (type==long):
- jl,jh = 0, 15
+ elif type == int:
+ jl = 0
+ elif type == long:
+ jl, jh = 0, 15
for i in range(il, ih+1):
- for j in range(jl,jh+1):
+ for j in range(jl, jh+1):
for k in range(kl, kh+1):
- if (k!=0):
+ if k != 0:
if compare(pow(type(i),j,k), pow(type(i),j)% type(k)):
raise ValueError, "pow(" +str(i)+ "," +str(j)+ \
"," +str(k)+ ") != pow(" +str(i)+ "," + \
@@ -81,15 +106,15 @@ print
for i in range(-10, 11):
for j in range(0, 6):
for k in range(-7, 11):
- if (j>=0 and k!=0):
- o=pow(i,j) % k
- n=pow(i,j,k)
- if (o!=n): print 'Integer mismatch:', i,j,k
- if (j>=0 and k<>0):
- o=pow(long(i),j) % k
- n=pow(long(i),j,k)
- if (o!=n): print 'Long mismatch:', i,j,k
- if (i>=0 and k<>0):
- o=pow(float(i),j) % k
- n=pow(float(i),j,k)
- if (o!=n): print 'Float mismatch:', i,j,k
+ if j >= 0 and k != 0:
+ o = pow(i,j) % k
+ n = pow(i,j,k)
+ if o != n: print 'Integer mismatch:', i,j,k
+ if j >= 0 and k <> 0:
+ o = pow(long(i),j) % k
+ n = pow(long(i),j,k)
+ if o != n: print 'Long mismatch:', i,j,k
+ if i >= 0 and k <> 0:
+ o = pow(float(i),j) % k
+ n = pow(float(i),j,k)
+ if o != n: print 'Float mismatch:', i,j,k