Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1201
diff -u -p -r1.1201 common.inc
--- includes/common.inc	5 Aug 2010 08:36:08 -0000	1.1201
+++ includes/common.inc	6 Aug 2010 07:02:13 -0000
@@ -1005,6 +1005,29 @@ function drupal_http_request($url, array
       $result->error = $status_message;
   }
 
+  // Errors are being sent via X-Drupal-Assertion-* headers, generated by
+  // _drupal_log_error() in the exact form required by
+  // DrupalWebTestCase::error().
+  if (!empty($result->headers)) {
+    $test_info = &$GLOBALS['drupal_test_info'];
+    $child_site = !empty($GLOBALS['drupal_test_info']['in_child_site']);
+    foreach ($result->headers as $name => $value) {
+      if (preg_match('/^x-drupal-assertion-[0-9]+$/', $name)) {
+        // If the request is being made inside another request (we are in the
+        // child site of a test making the call to drupal_http_request) then
+        // forward the errors back to the parent. An example of this is
+        // UpdateTestContribCase which calls admin/reports/updates/check which
+        // in term makes a drupal_http_request().
+        if ($child_site) {
+          header($name . ': ' . $value);
+        }
+        else {
+          call_user_func_array(array(&DrupalTestCase::$self, 'error'), unserialize(urldecode($value)));
+        }
+      }
+    }
+  }
+
   return $result;
 }
 /**
Index: modules/simpletest/drupal_web_test_case.php
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/drupal_web_test_case.php,v
retrieving revision 1.225
diff -u -p -r1.225 drupal_web_test_case.php
--- modules/simpletest/drupal_web_test_case.php	19 Jul 2010 21:54:46 -0000	1.225
+++ modules/simpletest/drupal_web_test_case.php	6 Aug 2010 07:02:14 -0000
@@ -19,6 +19,14 @@ global $drupal_test_info;
  * Do not extend this class, use one of the subclasses in this file.
  */
 abstract class DrupalTestCase {
+
+  /**
+   * Active DrupalTestCase instance.
+   *
+   * @var object
+   */
+  public static $self;
+
   /**
    * The test run ID.
    *
@@ -82,6 +90,7 @@ abstract class DrupalTestCase {
    */
   public function __construct($test_id = NULL) {
     $this->testId = $test_id;
+    self::$self = $this;
   }
 
   /**
@@ -392,6 +401,9 @@ abstract class DrupalTestCase {
   /**
    * Fire an error assertion.
    *
+   * Called from drupal_http_request() to record errors sent back through HTTP
+   * headers and thus it must be public.
+   *
    * @param $message
    *   The message to display along with the assertion.
    * @param $group
@@ -401,7 +413,7 @@ abstract class DrupalTestCase {
    * @return
    *   FALSE.
    */
-  protected function error($message = '', $group = 'Other', array $caller = NULL) {
+  public function error($message = '', $group = 'Other', array $caller = NULL) {
     if ($group == 'User notice') {
       // Since 'User notice' is set by trigger_error() which is used for debug
       // set the message to a status of 'debug'.
Index: modules/simpletest/tests/common.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/common.test,v
retrieving revision 1.119
diff -u -p -r1.119 common.test
--- modules/simpletest/tests/common.test	5 Aug 2010 23:53:38 -0000	1.119
+++ modules/simpletest/tests/common.test	6 Aug 2010 07:02:14 -0000
@@ -1724,7 +1724,7 @@ class DrupalErrorCollectionUnitTest exte
     }
   }
 
-  protected function error($message = '', $group = 'Other', array $caller = NULL) {
+  public function error($message = '', $group = 'Other', array $caller = NULL) {
     // This function overiddes DrupalWebTestCase::error(). We collect an error...
     $this->collectedErrors[] = array(
       'message' => $message,