[Phpmyadmin-devel] Mocking static methods - Unit tests

[Ayush Chaudhary]

On Tuesday, 9 July 2013 at 5:58 PM, Madhura Jayaratne wrote:
> 
> 
> 
> On Tue, Jul 9, 2013 at 2:21 PM, Ayush Chaudhary <ayushchd at gmail.com (mailto:ayushchd at gmail.com)> wrote:
> > Hi,  
> > 
> > I have been writing Unit Tests for classes and libraries under libraries/config/*. For isolation between different libraries, its preferred to mock certain functions. Since some of the code is functional, I tried to convert (for a start) libraries/config/validate.lib.php into a class with static methods. 
> > 
> > However, the issue here is that mocking static methods is not really possible with PHPUnit and there are a few workarounds I came across and would like to know which one should we go for, or if there is anything better that can be done. 
> > 
> > So, while the writer of PHPUnit specifies how to mock static methods here[0], its only possible if the static calls are to the same class.
> > 
> > For example, for testing FormDisplay::_validate, I need to mock PMA_config_validate. After I convert validate.lib.php to a class, say, PMA_Validator, I will have to mock PMA_Validator::config_validate, but the above solution won't work here (since PMA_Validator cannot be mocked). A workaround for this could be to pass the mocked static class as mentioned in [0] to the FormDisplay.class.php and make all static calls via that class. 
> > 
> > For this, we could have something of this sort in the constructor of FormDisplay:
> > 
> > if (defined('TESTSUITE'))
> > $this->validator = $GLOBALS['dummyValidator'] or $this->validator = <mockedClassPassedInTheArgument>
> > else
> > $this->validator = 'PMA_Validator'
> > 
> > and the calls can be made like:
> > 
> > $caller = $this->validator; // $this->validator::config_validate won't work 
> > $caller:config_validate();
> > 
> > Another solution could be what is mentioned in a blog here[1]. The problem with this solution is that the file, FormDisplay.class.php would include and hence declare the PMA_Validator class before our test suite tries to (re)declare it by extending MockProxy class. 
> > 
> > In either case, it looks like some sort of modification would be needed to test these classes.
> > 
> > Please advice.
> > 
> > [0] http://sebastian-bergmann.de/archives/883-Stubbing-and-Mocking-Static-Methods.html 
> > [1] http://www.deanspot.org/content/mocking-static-method-calls-phpunit
> > 
> > 
> As Sebastian Bergmann says, "static methods are death to testability".This makes me wonder what disadvantages we would have if we make the methods of PMA_Validator class non-static and use instantiated object of PMA_Validator class to do the validations?
> 
I doubt there would be any disadvantages. In any case, from the POV of Unit Testing, we will have to include the instantiated object or the class name, as a member of the class that calls the respective methods (in this example. FormDisplay)

Further, I'd like to know how useful this statement on PHP.net can be in this context:

'A property declared as static can not be accessed with an instantiated class object (though a static method can)'

> -- 
> Thanks and Regards,
> 
> Madhura Jayaratne
> 
> ------------------------------------------------------------------------------
> See everything from the browser to the database with AppDynamics
> Get end-to-end visibility with application monitoring from AppDynamics
> Isolate bottlenecks and diagnose root cause in seconds.
> Start your free trial of AppDynamics Pro today!
> http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk
> 
> _______________________________________________
> Phpmyadmin-devel mailing list
> Phpmyadmin-devel at lists.sourceforge.net (mailto:Phpmyadmin-devel at lists.sourceforge.net)
> https://lists.sourceforge.net/lists/listinfo/phpmyadmin-devel
> 
> 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.phpmyadmin.net/pipermail/developers/attachments/20130709/f6938e55/attachment.html>