Re: [Phpmyadmin-devel] Local static variable and unit testing

On Wednesday, 27 March 2013 at 5:29 PM, Dieter Adriaenssens wrote: 2013/3/26 Dieter Adriaenssens <dieter.adriaenssens(a)gmail.com (mailto:dieter.adriaenssens@gmail.com)>: 2013/3/24 Marc Delisle <marc(a)infomarc.info (mailto:marc@infomarc.info)>: Le 2013-03-23 11:07, Ayush Chaudhary a écrit : Hi On Saturday, 23 March 2013 at 8:24 PM, Marc Delisle wrote: Le 2013-03-23 08:47, Ayush Chaudhary a écrit : Hi, Hello, I was going through the existing tests. The test 'testIsHttps' under test/classes/PMA_Config_test.php looks wrong as isHttps() should be returning true for the second test case. However, the function isHttps() uses a local static variable, which is why the test is passing as in the construct, the PmaAbsoluteUri is initialised with null and isHttps() is hence returning false in all subsequent calls. I am not sure why a local static variable was used here. To avoid retesting the condition for nothing? A better test for this method would be if we could reset the static variable before each assertion. Since its a local static variable, I couldn't find a proper way to reset the static variable. Should we not move the static variable in the scope of the class? In fact, even if we don't use a static variable, we could just make is_https a class member and initialise it to NULL in the constructor. This would eventually achieve the same result in a neater way. Makes sense, but watch out: isHttps() and detectHttps() are both using $is_https, for different goals. Also, what approach do we take for resetting static variables if needed for unit testing? One thing I came across was using Reflection_Helper::set_static_variable($class, $name, $new_value)? Yes, this approach seems interesting : http://tech.blog.box.com/2012/07/unit-testing-with-static-variables/ I think the purpose of the static variable is to only let isHttps() execute once in the lifecycle of a PMA_Config object. Regarding, the use of $is_https in detectHttps(), the copy of $is_https in detectHttps() is completely independent of the one in isHttps() because isHttps() creates a local copy of the variable. So detectHttps() would not need to be changed at all. Yes, but on a maintenance perspective, it's confusing to be using the same variable in one file, with two different purposes. Making $is_https a member variable and using the member variable in isHttps() will help to make tests more exhaustive as we will be able to test for 1. non-https input 2. https input 3. input when is_https is already set (this is the only case that is being tested right now) Also, regarding that approach, the issue here is that the static copy has scope only within the function isHttps(), so it does not seem possible to reset it using Reflection_Helper. Please let me know, if this would be fine. I can then write a quick patch to fix this, and also improve testIsHttps() Please do; I am not the OOP expert of the team ;) I'm trying to figure out what is going on with $is_https in the PMA_Config class. I'll have another look at the code later and do some tests. I'll get back to you. is_https isn't a member variable of the PMA_Config class, and I'm wondering if it should be. In detectHttps() $is_https is a local variable. (only defined in the scope of this method) and this works. In isHttps() $is_https is made static, forcing it to be remembered, probably to avoid the behaviour as described in [0]. As I can see now, there are three things to be considered 1) use of static $is_https in isHttps() is not necessary -> it can be replace by something else that makes more sense in an instanciated class (like a class member variable, but because $this->settings["is_https"] already exists, it makes sense to use this one) The issue with using $this->settings['is_https'] would be that $this->settings['is_https'] is set by checkIsHttps() which in turn calls isHttps() So if in any case, isHttps() is called independently, it might cause issues. Since the purpose of static $is_https in isHttps() is precisely to make sure that isHttps() only sets $is_https to true or false only once in the life cycle of an object, we can have a class member like 'check_for_https' which is set to true in the constructor and then isHttps() checks if its true or false and if its true, isHttps() executes further and sets it to false.

2) the reason why $is_https is cached/stored in isHttps()? 3) the reason why isHttps() doesn't parse PmaAbsoluteUri when it is called a second time. (this is why the test returns a false when the method is called a second time with a url that contains https, if it would be a https url first and a http url second, it would return true two times) In case 2) and 3) I'm wondering why it is done this way. When it runs a second time, since $is_https already has a boolean value (true or false) and $is_https is a static variable in the scope of isHttps() and isHttps() returns $is_https if it already has a boolean value, the tests are returning the same results every time.

Michal, do you have any idea why this is done this way. It would make sense that isHttps() would not cache $is_https and would parse PmaAbsoluteUri every time, the execution is not expensive. That said, PmAbsoluteUri is not supposed to change because it is set in the configfile, so in a way caching does make sense. [0] http://sourceforge.net/p/phpmyadmin/bugs/2965/ -- Kind regards, Dieter Adriaenssens