On Fri, Jul 01, 2005 at 10:28:29AM -0700, Ovid wrote: > So, just for the sake of argument, imagine I write a class where I > periodically returns array refs to the user. I do this by building > them every time they're called. Later, I realize that my methods are > deterministic so I start caching results and returning them instead of > rebuilding the array each time. I'm expecting my test suite to still > continue working but under this proposed idea, it could be a nightmare > for me to debug. Heck, when I print out the arrays with Data::Dumper, > I'll see the same values and be mystified why they're not equivalent.
Another nail driven home. Ovid's given an example of how this violates encapsulation making it difficult to write black box tests which do not make assumptions about the implementation. Under Yves' suggestion if you replace a set of identical objects with a singleton your tests fail. This is wrong since the external interface did not change. This is consistent with is_deeply()'s positions on overloading, tying and blessing. "wrong" is relative because where I'm drawing the black box is a choice. Yves would have it be a bit deeper so the change from copied object to singleton becomes apparent. And maybe you do want that, if the objects are alterable then there could be an interface change as now altering one alters the other... or maybe it doesn't. Maybe its COW. Point is the line between "internal" and "external" expectations has to be drawn somewhere. I've drawn it a bit further out from true equivalency to ignore some differences which are usually inconsequential. Yves would like it pushed back to test true equivalency. The two positions cannot co-exist in the same function. One is not right nor wrong, they're just different functions. -- Michael G Schwern [EMAIL PROTECTED] http://www.pobox.com/~schwern Just call me 'Moron Sugar'. http://www.somethingpositive.net/sp05182002.shtml
