Don't initialize classes when registering matchers

[yas375]

It's possible that a library may have some assertions in theirs +initialize methods to help developers to find a potential problem in theirs setup. I.e. Facebook SDK makes sure you have specified required url scheme before you use FBSDKAppInviteDialog or FBSDKShareDialog, or FBSDKShareKit/FBSDKMessageDialog.

So we've just upgraded to the latest Facebook SDK and have started seeing exceptions when running tests. Those exceptions were exactly in those +initialize methods in FB sdk classes. But we don't use those features in our app so we don't need to set up all requirements it asserts for. It works fine when we run our apps because we never call those classes and theirs +initialize methods never called.

When we run tests KWMatcherFactory#registerMatcherClassesWithNamespacePrefix: is called and it loops through all available classes and check who conforms to KWMatching protocol. To check this, it uses NSObject#conformsToProtocol: which triggers +initialize call.

• initialize
  Initializes the class before it receives its first message.
  Discussion
  The runtime sends initialize to each class in a program just before the class, or any class that inherits from it, is sent its first message from within the program.

This doesn't look right. Kiwi doesn't need to trigger initialize methods for every class it can see in runtime. The solution is simply to use class_conformsToProtocol() function for this.

I believe this closes #637, #638, https://groups.google.com/forum/m/#!topic/kiwi-bdd/ZfLol8_Oz8k

[glentregoning]

👍 this PR, this is fixes the root cause of integration issues with Google Analytics / Facebook SDK (and others).

[IndieKevin]

+1 on the fix

[yas375]

Any feedback on this from maintainers please? Would be very nice to get it merged in. thanks in advance!

[glentregoning]

bump

It'd be great to get this fix onto master.

[ravelantunes]

Same issue here. Would be great to have it merged!

[ldrr]

Same issue here, could you please merge?

[gligorkot]

Same issue here, could you please merge this fix?

[orta]

OK, cool, looks good to me, let's do it.