Lib/test/test_pow.py

   1 import sys
   2 import test_support
   3
   4 def powtest(type):
   5     if type != float:
   6         print "    Testing 2-argument pow() function..."
   7         for i in range(-1000, 1000):
   8             if pow(type(i), 0) != 1:
   9                 raise ValueError, 'pow('+str(i)+',0) != 1'
  10             if pow(type(i), 1) != type(i):
  11                 raise ValueError, 'pow('+str(i)+',1) != '+str(i)
  12             if pow(type(0), 1) != type(0):
  13                 raise ValueError, 'pow(0,'+str(i)+') != 0'
  14             if pow(type(1), 1) != type(1):
  15                 raise ValueError, 'pow(1,'+str(i)+') != 1'
  16
  17         for i in range(-100, 100):
  18             if pow(type(i), 3) != i*i*i:
  19                 raise ValueError, 'pow('+str(i)+',3) != '+str(i*i*i)
  20
  21         pow2 = 1
  22         for i in range(0,31):
  23             if pow(2, i) != pow2:
  24                 raise ValueError, 'pow(2,'+str(i)+') != '+str(pow2)
  25             if i != 30 : pow2 = pow2*2
  26
  27         for othertype in int, long:
  28             for i in range(-10, 0) + range(1, 10):
  29                 ii = type(i)
  30                 for j in range(1, 11):
  31                     jj = -othertype(j)
  32                     try:
  33                         pow(ii, jj)
  34                     except ValueError:
  35                         pass # taking an int to a neg int power should fail
  36                     else:
  37                         raise ValueError, "pow(%s, %s) did not fail" % (ii, jj)
  38
  39     for othertype in int, long, float:
  40         for i in range(1, 100):
  41             zero = type(0)
  42             exp = -othertype(i/10.0)
  43             if exp == 0:
  44                 continue
  45             try:
  46                 pow(zero, exp)
  47             except ZeroDivisionError:
  48                 pass # taking zero to any negative exponent should fail
  49             else:
  50                 raise ValueError, "pow(%s, %s) did not fail" % (zero, exp)
  51
  52     print "    Testing 3-argument pow() function..."
  53     il, ih = -20, 20
  54     jl, jh = -5,   5
  55     kl, kh = -10, 10
  56     compare = cmp
  57     if type == float:
  58         il = 1
  59         compare = test_support.fcmp
  60     elif type == int:
  61         jl = 0
  62     elif type == long:
  63         jl, jh = 0, 15
  64     for i in range(il, ih+1):
  65         for j in range(jl, jh+1):
  66             for k in range(kl, kh+1):
  67                 if k != 0:
  68                     if compare(pow(type(i),j,k), pow(type(i),j)% type(k)):
  69                         raise ValueError, "pow(" +str(i)+ "," +str(j)+ \
  70                              "," +str(k)+ ") != pow(" +str(i)+ "," + \
  71                              str(j)+ ") % " +str(k)
  72
  73
  74 print 'Testing integer mode...'
  75 powtest(int)
  76 print 'Testing long integer mode...'
  77 powtest(long)
  78 print 'Testing floating point mode...'
  79 powtest(float)
  80
  81 # Other tests-- not very systematic
  82
  83 print 'The number in both columns should match.'
  84 print `pow(3,3) % 8`, `pow(3,3,8)`
  85 print `pow(3,3) % -8`, `pow(3,3,-8)`
  86 print `pow(3,2) % -2`, `pow(3,2,-2)`
  87 print `pow(-3,3) % 8`, `pow(-3,3,8)`
  88 print `pow(-3,3) % -8`, `pow(-3,3,-8)`
  89 print `pow(5,2) % -8`, `pow(5,2,-8)`
  90 print
  91
  92 print `pow(3L,3L) % 8`, `pow(3L,3L,8)`
  93 print `pow(3L,3L) % -8`, `pow(3L,3L,-8)`
  94 print `pow(3L,2) % -2`, `pow(3L,2,-2)`
  95 print `pow(-3L,3L) % 8`, `pow(-3L,3L,8)`
  96 print `pow(-3L,3L) % -8`, `pow(-3L,3L,-8)`
  97 print `pow(5L,2) % -8`, `pow(5L,2,-8)`
  98 print
  99
 100 print pow(3.0,3.0) % 8, pow(3.0,3.0,8)
 101 print pow(3.0,3.0) % -8, pow(3.0,3.0,-8)
 102 print pow(3.0,2) % -2, pow(3.0,2,-2)
 103 print pow(5.0,2) % -8, pow(5.0,2,-8)
 104 print
 105
 106 for i in range(-10, 11):
 107     for j in range(0, 6):
 108         for k in range(-7, 11):
 109             if j >= 0 and k != 0:
 110                 o = pow(i,j) % k
 111                 n = pow(i,j,k)
 112                 if o != n: print 'Integer mismatch:', i,j,k
 113             if j >= 0 and k != 0:
 114                 o = pow(long(i),j) % k
 115                 n = pow(long(i),j,k)
 116                 if o != n: print 'Long mismatch:', i,j,k
 117             if i >= 0 and k != 0:
 118                 o = pow(float(i),j) % k
 119                 n = pow(float(i),j,k)
 120                 if o != n: print 'Float mismatch:', i,j,k