Lib/test/test_pow.py

   1 import sys
   2 import test_support
   3
   4
   5 def powtest(type):
   6     if type != float:
   7         print "    Testing 2-argument pow() function..."
   8         for i in range(-1000, 1000):
   9             if pow(type(i), 0) != 1:
  10                 raise ValueError, 'pow('+str(i)+',0) != 1'
  11             if pow(type(i), 1) != type(i):
  12                 raise ValueError, 'pow('+str(i)+',1) != '+str(i)
  13             if pow(type(0), 1) != type(0):
  14                 raise ValueError, 'pow(0,'+str(i)+') != 0'
  15             if pow(type(1), 1) != type(1):
  16                 raise ValueError, 'pow(1,'+str(i)+') != 1'
  17
  18         for i in range(-100, 100):
  19             if pow(type(i), 3) != i*i*i:
  20                 raise ValueError, 'pow('+str(i)+',3) != '+str(i*i*i)
  21
  22         pow2 = 1
  23         for i in range(0,31):
  24             if pow(2, i) != pow2:
  25                 raise ValueError, 'pow(2,'+str(i)+') != '+str(pow2)
  26             if i != 30 : pow2 = pow2*2
  27
  28         for othertype in int, long:
  29             for i in range(-10, 0) + range(1, 10):
  30                 ii = type(i)
  31                 for j in range(1, 11):
  32                     jj = -othertype(j)
  33                     try:
  34                         pow(ii, jj)
  35                     except ValueError:
  36                         raise ValueError, "pow(%s, %s) failed" % (ii, jj)
  37
  38     for othertype in int, long, float:
  39         for i in range(1, 100):
  40             zero = type(0)
  41             exp = -othertype(i/10.0)
  42             if exp == 0:
  43                 continue
  44             try:
  45                 pow(zero, exp)
  46             except ZeroDivisionError:
  47                 pass # taking zero to any negative exponent should fail
  48             else:
  49                 raise ValueError, "pow(%s, %s) did not fail" % (zero, exp)
  50
  51     print "    Testing 3-argument pow() function..."
  52     il, ih = -20, 20
  53     jl, jh = -5,   5
  54     kl, kh = -10, 10
  55     compare = cmp
  56     if type == float:
  57         il = 1
  58         compare = test_support.fcmp
  59     elif type == int:
  60         jl = 0
  61     elif type == long:
  62         jl, jh = 0, 15
  63     for i in range(il, ih+1):
  64         for j in range(jl, jh+1):
  65             for k in range(kl, kh+1):
  66                 if k != 0:
  67                     if type == float or j < 0:
  68                         try:
  69                             pow(type(i),j,k)
  70                         except TypeError:
  71                             pass
  72                         else:
  73                             raise TestFailed("expected TypeError from "
  74                                 "pow%r" % ((type(i), j, k)))
  75                         continue
  76                     if compare(pow(type(i),j,k), pow(type(i),j)% type(k)):
  77                         raise ValueError, "pow(" +str(i)+ "," +str(j)+ \
  78                              "," +str(k)+ ") != pow(" +str(i)+ "," + \
  79                              str(j)+ ") % " +str(k)
  80
  81
  82 print 'Testing integer mode...'
  83 powtest(int)
  84 print 'Testing long integer mode...'
  85 powtest(long)
  86 print 'Testing floating point mode...'
  87 powtest(float)
  88
  89 # Other tests-- not very systematic
  90
  91 print 'The number in both columns should match.'
  92 print `pow(3,3) % 8`, `pow(3,3,8)`
  93 print `pow(3,3) % -8`, `pow(3,3,-8)`
  94 print `pow(3,2) % -2`, `pow(3,2,-2)`
  95 print `pow(-3,3) % 8`, `pow(-3,3,8)`
  96 print `pow(-3,3) % -8`, `pow(-3,3,-8)`
  97 print `pow(5,2) % -8`, `pow(5,2,-8)`
  98 print
  99
 100 print `pow(3L,3L) % 8`, `pow(3L,3L,8)`
 101 print `pow(3L,3L) % -8`, `pow(3L,3L,-8)`
 102 print `pow(3L,2) % -2`, `pow(3L,2,-2)`
 103 print `pow(-3L,3L) % 8`, `pow(-3L,3L,8)`
 104 print `pow(-3L,3L) % -8`, `pow(-3L,3L,-8)`
 105 print `pow(5L,2) % -8`, `pow(5L,2,-8)`
 106 print
 107
 108 print
 109
 110 for i in range(-10, 11):
 111     for j in range(0, 6):
 112         for k in range(-7, 11):
 113             if j >= 0 and k != 0:
 114                 o = pow(i,j) % k
 115                 n = pow(i,j,k)
 116                 if o != n: print 'Integer mismatch:', i,j,k
 117             if j >= 0 and k != 0:
 118                 o = pow(long(i),j) % k
 119                 n = pow(long(i),j,k)
 120                 if o != n: print 'Integer mismatch:', i,j,k