Example:

http://www.python.org/dev/buildbot/all/builders/x86%20FreeBSD%207.2%203.x/builds/1609/steps/test/logs/stdio

======================================================================
FAIL: test_source (test.test_collections.TestNamedTuple)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/test_collections.py", line 334, in test_source
    self.assertNotIn('Color', globals())
AssertionError: 'Color' unexpectedly found in {'OrderedDict': <class 'collections.OrderedDict'>, 'forget': <function forget at 0x28e89b34>, 'unittest': <module 'unittest' from '/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/__init__.py'>, 'MyOrderedDict': <class 'test.test_collections.MyOrderedDict'>, 'WithSet': <class 'test.test_collections.WithSet'>, 'KeysView': <class 'collections.abc.KeysView'>, 'operator': <module 'operator' (built-in)>, 'shuffle': <bound method Random.shuffle of <random.Random object at 0x286ff014>>, 'TestNT': <class 'test.test_collections.TestNT'>, 'MutableMapping': <class 'collections.abc.MutableMapping'>, 'randrange': <bound method Random.randrange of <random.Random object at 0x286ff014>>, 'unlink': <function unlink at 0x28e89a2c>, 'support': <module 'test.support' from '/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/support.py'>, 'Mapping': <class 'collections.abc.Mapping'>, '__package__': None, 'Callable': <class 'collections.abc.Callable'>, 're': <module 're' from '/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/re.py'>, 'TestCounter': <class 'test.test_collections.TestCounter'>, 'collections': <module 'collections' from '/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/collections/__init__.py'>, 'test_main': <function test_main at 0x2c6da8cc>, 'SubclassMappingTests': <class 'test.test_collections.SubclassMappingTests'>, 'ChainMap': <class 'collections.ChainMap'>, '__doc__': 'Unit tests for collections.py.', 'Hashable': <class 'collections.abc.Hashable'>, 'namedtuple': <function namedtuple at 0x2860a7c4>, 'inspect': <module 'inspect' from '/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/inspect.py'>, 'MutableSet': <class 'collections.abc.MutableSet'>, '__builtins__': {'bytearray': <class 'bytearray'>, 'IndexError': <class 'IndexError'>, 'all': <built-in function all>, 'help': Type help() for interactive help, or help(object) for help about object., 'vars': <built-in function vars>, 'SyntaxError': <class 'SyntaxError'>, 'UnicodeDecodeError': <class 'UnicodeDecodeError'>, 'memoryview': <class 'memoryview'>, 'isinstance': <built-in function isinstance>, '__build_class__': <built-in function __build_class__>, 'copyright': Copyright (c) 2001-2011 Python Software Foundation.

Link to the commit: f09f7ab40ce6

Thanks for the report.  It looks like globals() contamination is happening on the buildbot that isn't happening locally.

Isolated the test in commit 4f1cd92fe835

Will check the buildbots after to make sure it worked.  Otherwise, will delete test.

Why do you remove NTColor from globals *after* creating it? The assertion looks useless, or are you testing that globals().pop() works as expected?

tmp = namedtuple('NTColor', 'red green blue')
globals().pop('NTColor', None)          # remove artifacts from other tests
self.assertNotIn('NTColor', globals())

Can't you remove NTColor from globals before creating it?

globals().pop('NTColor', None)
tmp = namedtuple('NTColor', 'red green blue')
self.assertNotIn('NTColor', globals())

It looks like I missed something important :-)