Re: Unit testing, context and wantarray

how do I test that a function returns nothing when called in void context?

Two thoughts:

Why would it matter?
If a function returned a value in a void context, it is just discarded.
Not returning anything in a void context is not the point, it is not calculating the return values if they are never going to be used that makes a difference.
Testing something that is obvious by inspection is a waste of time.
If the first line of the sub is return unless defined wantarray;, the sub will not return anything when called in a void context. There is no need to test that.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^2: Unit testing, context and wantarray by mikeman (Acolyte) on Aug 13, 2011 at 11:22 UTC
Thanks for your reply. I think you answer has pointed me in the right direction: I am trying to test for the wrong thing. I should be testing (perhaps via a mock object or similar), that my function does not do anything expensive (e.g., call a database function) to return a result when called in void context. I was erroneously focusing on the return result, rather than the operations of my function. Testing the return value (or lack thereof) would not prove if my function was performing a pointless operation. Thanks!	[reply]
Re^3: Unit testing, context and wantarray by GrandFather (Saint) on Aug 13, 2011 at 11:33 UTC
As a general thing though, one may often call a method in a void context and expect something expensive to happen (connecting to a remote database for example), especially if you use exception handling to manage errors rather than passing error states back. True laziness is hard work	[reply]
Re^3: Unit testing, context and wantarray by eyepopslikeamosquito (Archbishop) on Aug 13, 2011 at 11:43 UTC
I should be testing (perhaps via a mock object or similar), that my function does not do anything expensive (e.g., call a database function) to return a result when called in void context. Such as playing nethack? :)	[reply]
Re^4: Unit testing, context and wantarray by FunkyMonk (Bishop) on Aug 13, 2011 at 14:15 UTC
www.nntp.perl.org seems dead at the moment. Here's Google's cached page Perl: perlintro perlretut Basic debugging checklist PerlMonks: How do I post a question effectively? Markup in the Monastery How do I post a question effectively? I know what I mean. Why don't you? General: How To Ask Questions The Smart Way What every computer scientist should know about floating-point arithmetic To Be Continued...	[reply]