From: Scott Meyers (usenet_at_[hidden])
Date: 2006-09-14 00:59:50
Rush Manbert wrote:
> In a case like the example, where I know it might be hard to setup the
> object correctly, I'd rather have a constructor that took some bogus
> argument type that set the object up in "simulated success" mode, but
> only in my debug build.
I'm glad you mentioned this, because my recent knowledge of unit testing
comes from books like Beck's "Test-Driven Development" and Feathers'
"Working Effectively with Legacy Code" as well as countless breathless
articles lauding the wonder of unit testing and showing how it's all
oh-so-simple. My feeling is that it would often be convenient to have a
special "test" interface, but I've never seen any discussion of doing
that. I can imagine a couple of ways of doing this, one being to
literally have a different interface for debug builds, another to have
"test only" interface elements cordoned off somewhere by convention
(similar to Boost's use of namespaces named "detail").
> EventLog::EventLog (bool dummyarg)
> { // This constructor sets us up in simulated success mode.
> #ifdef DEBUG // or whatever you use
> m_simulateSuccess = true;
> #else
> throw something useful
> #endif
> }
Hmmm, I'd think this entire constructor would exist only in debug
builds, e.g.,
class EventLog {
public:
#ifdef DEBUG
EventLog(bool dummyarg);
#endif
Unfortunately, conditional compilation is not without its own resultant
spaghetti code and concomitant maintenance headaches.
Scott