Added docs.

src/Framework/Exception.php

@@ -44,6 +44,25 @@
  */
 
 /**
+ * Base class for all PHPUnit Framework exceptions.
+ *
+ * Ensures that exceptions thrown during a test run do not leave stray
+ * references behind.
+ *
+ * Every Exception contains a stack trace. Each stack frame contains the 'args'
+ * of the called function. The function arguments can contain references to
+ * instantiated objects. The references prevent the objects from being
+ * destructed (until test results are eventually printed), so memory cannot be
+ * freed up.
+ *
+ * With enabled process isolation, test results are serialized in the child
+ * process and unserialized in the parent process. The stack trace of Exceptions
+ * may contain objects that cannot be serialized or unserialized (e.g., PDO
+ * connections). Unserializing user-space objects from the child process into
+ * the parent would break the intended encapsulation of process isolation.
+ *
+ * @see http://fabien.potencier.org/article/9/php-serialization-stack-traces-and-exceptions
+ *
  * @package    PHPUnit
  * @subpackage Framework
  * @author     Sebastian Bergmann <sebastian@phpunit.de>

src/Framework/ExceptionWrapper.php

@@ -44,6 +44,14 @@
  */
 
 /**
+ * Wraps Exceptions thrown by code under test.
+ *
+ * Re-instantiates Exceptions thrown by user-space code to retain their original
+ * class names, properties, and stack traces (but without arguments).
+ *
+ * Unlike PHPUnit_Framework_Exception, the complete stack of previous Exceptions
+ * is processed.
+ *
  * @package    PHPUnit
  * @subpackage Framework
  * @author     Daniel F. Kudwien <sun@unleashedmind.com>