unit tests: MDL-17803 test classes were not getting destroyed at the right time, which was breaking the code that reset the test DB to the normal DB.

lib/simpletestlib/moodle_readme.txt

@@ -0,0 +1,10 @@
+Description of SimpleTest Version: 1.0.1 library import
+
+Obtained from http://www.simpletest.org/en/download.html
+
+Moodle-specific changes:
+* Bug fix in simpletest.php and test_case.php. Marked with //moodlefix begins,
+  //moodlefix ends comments. This has been reported back to the simpletest mailing
+  list. Hopefully will be included in a future release.
+
+Tim.

lib/simpletestlib/simpletest.php

@@ -276,6 +276,19 @@ class SimpleTestContext {
         $this->_test = &$test;
     }
 
+//moodlefix begins
+    /**
+     *    Unsets the current test case instance. Avoids
+     *    problems when test classes rely on their destructors
+     *    being called at a predictable time.
+     *    @access public
+     */
+    function unsetTest() {
+        $this->clear();
+        $this->_test = NULL;
+    }
+
+//moodlefix ends
     /**
      *    Accessor for currently running test case.
      *    @return SimpleTestCase    Current test.

lib/simpletestlib/test_case.php

@@ -148,6 +148,9 @@ class SimpleTestCase {
             $reporter->paintCaseEnd($this->getLabel());
         }
         unset($this->_reporter);
+//moodlefix begins
+        $context->unsetTest();
+//moodlefix ends
         return $reporter->getStatus();
     }