Lib/test/test_long_future.py

   1 from __future__ import division
   2 # When true division is the default, get rid of this and add it to
   3 # test_long.py instead.  In the meantime, it's too obscure to try to
   4 # trick just part of test_long into using future division.
   5
   6 from test.test_support import TestFailed, verify, verbose
   7
   8 def test_true_division():
   9     if verbose:
  10         print "long true division"
  11     huge = 1L << 40000
  12     mhuge = -huge
  13     verify(huge / huge == 1.0)
  14     verify(mhuge / mhuge == 1.0)
  15     verify(huge / mhuge == -1.0)
  16     verify(mhuge / huge == -1.0)
  17     verify(1 / huge == 0.0)
  18     verify(1L / huge == 0.0)
  19     verify(1 / mhuge == 0.0)
  20     verify(1L / mhuge == 0.0)
  21     verify((666 * huge + (huge >> 1)) / huge == 666.5)
  22     verify((666 * mhuge + (mhuge >> 1)) / mhuge == 666.5)
  23     verify((666 * huge + (huge >> 1)) / mhuge == -666.5)
  24     verify((666 * mhuge + (mhuge >> 1)) / huge == -666.5)
  25     verify(huge / (huge << 1) == 0.5)
  26     verify((1000000 * huge) / huge == 1000000)
  27
  28     namespace = {'huge': huge, 'mhuge': mhuge}
  29
  30     for overflow in ["float(huge)", "float(mhuge)",
  31                      "huge / 1", "huge / 2L", "huge / -1", "huge / -2L",
  32                      "mhuge / 100", "mhuge / 100L"]:
  33         try:
  34             eval(overflow, namespace)
  35         except OverflowError:
  36             pass
  37         else:
  38             raise TestFailed("expected OverflowError from %r" % overflow)
  39
  40     for underflow in ["1 / huge", "2L / huge", "-1 / huge", "-2L / huge",
  41                      "100 / mhuge", "100L / mhuge"]:
  42         result = eval(underflow, namespace)
  43         if result != 0.0:
  44             raise TestFailed("expected underflow to 0 from %r" % underflow)
  45
  46     for zero in ["huge / 0", "huge / 0L",
  47                  "mhuge / 0", "mhuge / 0L"]:
  48         try:
  49             eval(zero, namespace)
  50         except ZeroDivisionError:
  51             pass
  52         else:
  53             raise TestFailed("expected ZeroDivisionError from %r" % zero)
  54
  55 test_true_division()