(Yaf >=1.0.0)
Yaf_Application provides a bootstrapping facility for applications which provides reusable resources, common- and module-based bootstrap classes and dependency checking.
Nota:
Yaf_Application implements the singleton pattern, and Yaf_Application can not be serialized or unserialized which will cause problem when you try to use PHPUnit to write some test case for Yaf.
You may use @backupGlobals annotation of PHPUnit to control the backup and restore operations for global variables. thus can solve this problem.