cpython/Lib/test/test_pow.py

import sys
import test_support

def powtest(type):
    if (type!=float): 
        print "    Testing 2-argument pow() function..."
        for i in range(-1000, 1000):
            if (pow(type(i),0)!=1): 
                raise ValueError, 'pow('+str(i)+',0) != 1'
            if (pow(type(i),1)!=type(i)):
                raise ValueError, 'pow('+str(i)+',1) != '+str(i)
            if (pow(type(0),1)!=type(0)):
                raise ValueError, 'pow(0,'+str(i)+') != 0'
            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):
                raise ValueError, 'pow('+str(i)+',3) != '+str(i*i*i)
    
        pow2=1
        for i in range(0,31):
            if (pow(2,i)!=pow2):
                raise ValueError, 'pow(2,'+str(i)+') != '+str(pow2)
            if (i!=30): pow2=pow2*2

    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
        compare = test_support.fcmp
    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 k in range(kl, kh+1):
                 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)+ "," + \
                              str(j)+ ") % " +str(k)


print 'Testing integer mode...'
powtest(int)
print 'Testing long integer mode...'
powtest(long)
print 'Testing floating point mode...'
powtest(float)

# Other tests-- not very systematic

print 'The number in both columns should match.'
print `pow(3,3) % 8`, `pow(3,3,8)`
print `pow(3,3) % -8`, `pow(3,3,-8)`
print `pow(3,2) % -2`, `pow(3,2,-2)`
print `pow(-3,3) % 8`, `pow(-3,3,8)`
print `pow(-3,3) % -8`, `pow(-3,3,-8)`
print `pow(5,2) % -8`, `pow(5,2,-8)`
print

print `pow(3L,3L) % 8`, `pow(3L,3L,8)`
print `pow(3L,3L) % -8`, `pow(3L,3L,-8)`
print `pow(3L,2) % -2`, `pow(3L,2,-2)`
print `pow(-3L,3L) % 8`, `pow(-3L,3L,8)`
print `pow(-3L,3L) % -8`, `pow(-3L,3L,-8)`
print `pow(5L,2) % -8`, `pow(5L,2,-8)`
print

print pow(3.0,3.0) % 8, pow(3.0,3.0,8)
print pow(3.0,3.0) % -8, pow(3.0,3.0,-8)
print pow(3.0,2) % -2, pow(3.0,2,-2)
print pow(5.0,2) % -8, pow(5.0,2,-8)
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