[Python-Dev] PEP: Consolidating names and classes in the unittest module (original) (raw)

Steve Holden steve at holdenweb.com
Tue Jul 15 08:21:01 CEST 2008

Michael Foord wrote:

Benjamin Peterson wrote:

On Mon, Jul 14, 2008 at 6:18 PM, Ben Finney <ben+python at benfinney.id.au> wrote:

"Benjamin Peterson" <musiccomposition at gmail.com> writes:

On Mon, Jul 14, 2008 at 8:25 AM, Ben Finney <ben+python at benfinney.id.au> wrote: Use new-style classes throughout -------------------------------- The following classes will inherit explicitly from the built-in object type, to make all classes in the module part of the new-style type hierarchy. * TestResult * TestCase * TestSuite * TestLoader * WritelnDecorator * TextTestRunner * TestProgram They already do. metaclass = type is found in unittest.py. Not in the copy I have. Is that in 3.x only, or in 2.x also? Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53) [GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin Type "help", "copyright", "credits" or "license" for more information. import unittest isinstance(unittest.TestCase, object) True That proves nothing: Python 2.5.2 (r252:60911, Feb 22 2008, 07:57:53) [GCC 4.0.1 (Apple Computer, Inc. build 5363)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> class x: pass ... >>> isinstance(x, object) True >>> isinstance(x, type) False >>> type(x) <type 'classobj'> Shouldn't isinstance(x, object) be True for any x in recent CPythons (and hopefully the other implementations too)? It's certainly so for functions and modules, for , as well as the less esoteric types and instances of classic classes.

Something that often ties students' heads in knots (and this isn't from the introductory course):

isinstance(type, object) True isinstance(object, type) True

This is a classic property of general object hierarchies based on metaclasses. I remember teaching the SmallTalk-80 equivalent to M.Sc. studnets in the early 1980s, though the details are now lost in the mists of time. Eyes would always widen, and not everyone would get it.

regards Steve

Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/

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