After applying the patch make sure, that svn:ignore SVN property on /install/cache in all modules (including core) matches value from the .gitignore file in that folder.

1. perform installation of In-Portal (without modules and with some/all modules)
2. confirm, that it's possible
3. open In-Portal and do some common stuff, like browsing Front-End/Admin Console
4. confirm, that no error happens
5. create any class, e.g. new helper and don't register it in any unit config
6. run php tools/build_class_map.php script
7. confirm, that new class mention was added to a /install/cache/class_map.php file of module, where you've added the class
8. try using the helper like $this->Application->recallObject('HelperClassName');
9. confirm, that proper class instance was created
10. register helper class under different (than class name) pseudo without specifying file key during registration
11. try using the helper like $this->Application->recallObject('HelperPseudoName');
12. confirm, that proper class instance was created
13. create another helper class, but this time don't run class map update script
14. try using the helper like $this->Application->recallObject('AnotherHelperClassName');
15. confirm, that exception is thrown with suggestion to use class map rebuild script
16. repeat last 3 steps but use makeClass method instead (before direct makeClass call on wrong class would end up in weird error)
17. confirm, that classes, interfaces and traits are all discovered and placed into classmap