cpython/Lib/test/test_operations.py
Tim Peters 9a828d3c61 BadDictKey test: The output file expected "raising error" to be printed
exactly once.  But the test code can't know that, as the number of times
__cmp__ is called depends on internal details of the dict implementation.
This is especially nasty because the __hash__ method returns the address
of the class object, so the hash codes seen by the dict can vary across
runs, causing the dict to use a different probe order across runs.  I
just happened to see this test fail about 1 run in 7 today, but only
under a release build and when passing -O to Python.  So, changed the test
to be predictable across runs.
2001-05-29 21:14:32 +00:00

53 lines
1.7 KiB
Python

# Python test set -- part 3, built-in operations.
print '3. Operations'
print 'XXX Mostly not yet implemented'
print '3.1 Dictionary lookups succeed even if __cmp__() raises an exception'
# SourceForge bug #112558:
# http://sourceforge.net/bugs/?func=detailbug&bug_id=112558&group_id=5470
class BadDictKey:
already_printed_raising_error = 0
def __hash__(self):
return hash(self.__class__)
def __cmp__(self, other):
if isinstance(other, self.__class__):
if not BadDictKey.already_printed_raising_error:
# How many times __cmp__ gets called depends on the hash
# code and the internals of the dict implementation; we
# know it will be called at least once, but that's it.
# already_printed_raising_error makes sure the expected-
# output file prints the msg at most once.
BadDictKey.already_printed_raising_error = 1
print "raising error"
raise RuntimeError, "gotcha"
return other
d = {}
x1 = BadDictKey()
x2 = BadDictKey()
d[x1] = 1
d[x2] = 2
print "No exception passed through."
# Dict resizing bug, found by Jack Jansen in 2.2 CVS development.
# This version got an assert failure in debug build, infinite loop in
# release build. Unfortunately, provoking this kind of stuff requires
# a mix of inserts and deletes hitting exactly the right hash codes in
# exactly the right order, and I can't think of a randomized approach
# that would be *likely* to hit a failing case in reasonable time.
d = {}
for i in range(5):
d[i] = i
for i in range(5):
del d[i]
for i in range(5, 9): # i==8 was the problem
d[i] = i