test_pow.py 4.5 KB

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  1. import test.test_support, unittest
  2. class PowTest(unittest.TestCase):
  3. def powtest(self, type):
  4. if type != float:
  5. for i in range(-1000, 1000):
  6. self.assertEqual(pow(type(i), 0), 1)
  7. self.assertEqual(pow(type(i), 1), type(i))
  8. self.assertEqual(pow(type(0), 1), type(0))
  9. self.assertEqual(pow(type(1), 1), type(1))
  10. for i in range(-100, 100):
  11. self.assertEqual(pow(type(i), 3), i*i*i)
  12. pow2 = 1
  13. for i in range(0,31):
  14. self.assertEqual(pow(2, i), pow2)
  15. if i != 30 : pow2 = pow2*2
  16. for othertype in int, long:
  17. for i in range(-10, 0) + range(1, 10):
  18. ii = type(i)
  19. for j in range(1, 11):
  20. jj = -othertype(j)
  21. pow(ii, jj)
  22. for othertype in int, long, float:
  23. for i in range(1, 100):
  24. zero = type(0)
  25. exp = -othertype(i/10.0)
  26. if exp == 0:
  27. continue
  28. self.assertRaises(ZeroDivisionError, pow, zero, exp)
  29. il, ih = -20, 20
  30. jl, jh = -5, 5
  31. kl, kh = -10, 10
  32. asseq = self.assertEqual
  33. if type == float:
  34. il = 1
  35. asseq = self.assertAlmostEqual
  36. elif type == int:
  37. jl = 0
  38. elif type == long:
  39. jl, jh = 0, 15
  40. for i in range(il, ih+1):
  41. for j in range(jl, jh+1):
  42. for k in range(kl, kh+1):
  43. if k != 0:
  44. if type == float or j < 0:
  45. self.assertRaises(TypeError, pow, type(i), j, k)
  46. continue
  47. asseq(
  48. pow(type(i),j,k),
  49. pow(type(i),j)% type(k)
  50. )
  51. def test_powint(self):
  52. self.powtest(int)
  53. def test_powlong(self):
  54. self.powtest(long)
  55. def test_powfloat(self):
  56. self.powtest(float)
  57. def test_other(self):
  58. # Other tests-- not very systematic
  59. self.assertEqual(pow(3,3) % 8, pow(3,3,8))
  60. self.assertEqual(pow(3,3) % -8, pow(3,3,-8))
  61. self.assertEqual(pow(3,2) % -2, pow(3,2,-2))
  62. self.assertEqual(pow(-3,3) % 8, pow(-3,3,8))
  63. self.assertEqual(pow(-3,3) % -8, pow(-3,3,-8))
  64. self.assertEqual(pow(5,2) % -8, pow(5,2,-8))
  65. self.assertEqual(pow(3L,3L) % 8, pow(3L,3L,8))
  66. self.assertEqual(pow(3L,3L) % -8, pow(3L,3L,-8))
  67. self.assertEqual(pow(3L,2) % -2, pow(3L,2,-2))
  68. self.assertEqual(pow(-3L,3L) % 8, pow(-3L,3L,8))
  69. self.assertEqual(pow(-3L,3L) % -8, pow(-3L,3L,-8))
  70. self.assertEqual(pow(5L,2) % -8, pow(5L,2,-8))
  71. for i in range(-10, 11):
  72. for j in range(0, 6):
  73. for k in range(-7, 11):
  74. if j >= 0 and k != 0:
  75. self.assertEqual(
  76. pow(i,j) % k,
  77. pow(i,j,k)
  78. )
  79. if j >= 0 and k != 0:
  80. self.assertEqual(
  81. pow(long(i),j) % k,
  82. pow(long(i),j,k)
  83. )
  84. def test_bug643260(self):
  85. class TestRpow:
  86. def __rpow__(self, other):
  87. return None
  88. None ** TestRpow() # Won't fail when __rpow__ invoked. SF bug #643260.
  89. def test_bug705231(self):
  90. # -1.0 raised to an integer should never blow up. It did if the
  91. # platform pow() was buggy, and Python didn't worm around it.
  92. eq = self.assertEqual
  93. a = -1.0
  94. # The next two tests can still fail if the platform floor()
  95. # function doesn't treat all large inputs as integers
  96. # test_math should also fail if that is happening
  97. eq(pow(a, 1.23e167), 1.0)
  98. eq(pow(a, -1.23e167), 1.0)
  99. for b in range(-10, 11):
  100. eq(pow(a, float(b)), b & 1 and -1.0 or 1.0)
  101. for n in range(0, 100):
  102. fiveto = float(5 ** n)
  103. # For small n, fiveto will be odd. Eventually we run out of
  104. # mantissa bits, though, and thereafer fiveto will be even.
  105. expected = fiveto % 2.0 and -1.0 or 1.0
  106. eq(pow(a, fiveto), expected)
  107. eq(pow(a, -fiveto), expected)
  108. eq(expected, 1.0) # else we didn't push fiveto to evenness
  109. def test_main():
  110. test.test_support.run_unittest(PowTest)
  111. if __name__ == "__main__":
  112. test_main()