Lib/test/test_operations.py

   1 # Python test set -- part 3, built-in operations.
   2
   3
   4 print '3. Operations'
   5 print 'XXX Mostly not yet implemented'
   6
   7
   8 print '3.1 Dictionary lookups succeed even if __cmp__() raises an exception'
   9
  10 # SourceForge bug #112558:
  11 # http://sourceforge.net/bugs/?func=detailbug&bug_id=112558&group_id=5470
  12
  13 class BadDictKey:
  14     already_printed_raising_error = 0
  15
  16     def __hash__(self):
  17         return hash(self.__class__)
  18
  19     def __cmp__(self, other):
  20         if isinstance(other, self.__class__):
  21             if not BadDictKey.already_printed_raising_error:
  22                 # How many times __cmp__ gets called depends on the hash
  23                 # code and the internals of the dict implementation; we
  24                 # know it will be called at least once, but that's it.
  25                 # already_printed_raising_error makes sure the expected-
  26                 # output file prints the msg at most once.
  27                 BadDictKey.already_printed_raising_error = 1
  28                 print "raising error"
  29             raise RuntimeError, "gotcha"
  30         return other
  31
  32 d = {}
  33 x1 = BadDictKey()
  34 x2 = BadDictKey()
  35 d[x1] = 1
  36 d[x2] = 2
  37 print "No exception passed through."
  38
  39 # Dict resizing bug, found by Jack Jansen in 2.2 CVS development.
  40 # This version got an assert failure in debug build, infinite loop in
  41 # release build.  Unfortunately, provoking this kind of stuff requires
  42 # a mix of inserts and deletes hitting exactly the right hash codes in
  43 # exactly the right order, and I can't think of a randomized approach
  44 # that would be *likely* to hit a failing case in reasonable time.
  45
  46 d = {}
  47 for i in range(5):
  48     d[i] = i
  49 for i in range(5):
  50     del d[i]
  51 for i in range(5, 9):  # i==8 was the problem
  52     d[i] = i