diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 052e0b7..19894b5 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -171,14 +171,17 @@ function simpletest_run_tests($test_list) {
  * @param $unescaped_test_classnames
  *   An array of test class names, including full namespaces, to be passed as
  *   a regular expression to PHPUnit's --filter option.
+ * @param int $status
+ *   (optional) The exit status code of the PHPUnit process will be assigned to
+ *   this variable.
  *
  * @return array
  *   The parsed results of PHPUnit's JUnit XML output, in the format of
  *   {simpletest}'s schema.
  */
-function simpletest_run_phpunit_tests($test_id, array $unescaped_test_classnames) {
+function simpletest_run_phpunit_tests($test_id, array $unescaped_test_classnames, &$status = NULL) {
   $phpunit_file = simpletest_phpunit_xml_filepath($test_id);
-  simpletest_phpunit_run_command($unescaped_test_classnames, $phpunit_file);
+  simpletest_phpunit_run_command($unescaped_test_classnames, $phpunit_file, $status);
   return simpletest_phpunit_xml_to_rows($test_id, $phpunit_file);
 }
 
@@ -233,11 +236,14 @@ function simpletest_phpunit_configuration_filepath() {
  *   a regular expression to PHPUnit's --filter option.
  * @param string $phpunit_file
  *   A filepath to use for PHPUnit's --log-junit option.
+ * @param int $status
+ *   (optional) The exit status code of the PHPUnit process will be assigned to
+ *   this variable.
  *
  * @return string
  *  The results as returned by exec().
  */
-function simpletest_phpunit_run_command(array $unescaped_test_classnames, $phpunit_file) {
+function simpletest_phpunit_run_command(array $unescaped_test_classnames, $phpunit_file, &$status = NULL) {
   $phpunit_bin = simpletest_phpunit_command();
 
   $command = array(
@@ -271,7 +277,7 @@ function simpletest_phpunit_run_command(array $unescaped_test_classnames, $phpun
 
   // exec in a subshell so that the environment is isolated when running tests
   // via the simpletest UI.
-  $ret = exec(join($command, " "));
+  $ret = exec(join($command, " "), $output, $status);
   chdir($old_cwd);
   return $ret;
 }
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 4e35b28..3a2951c 100644
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -20,12 +20,16 @@ const SIMPLETEST_SCRIPT_COLOR_EXCEPTION = 33; // Brown.
 // Restricting the chunk of queries prevents memory exhaustion.
 const SIMPLETEST_SCRIPT_SQLITE_VARIABLE_LIMIT = 350;
 
+const SIMPLETEST_SCRIPT_EXIT_SUCCESS = 0;
+const SIMPLETEST_SCRIPT_EXIT_FAILURE = 1;
+const SIMPLETEST_SCRIPT_EXIT_EXCEPTION = 2;
+
 // Set defaults and get overrides.
 list($args, $count) = simpletest_script_parse_args();
 
 if ($args['help'] || $count == 0) {
   simpletest_script_help();
-  exit;
+  exit(($count == 0) ? SIMPLETEST_SCRIPT_EXIT_FAILURE : SIMPLETEST_SCRIPT_EXIT_SUCCESS);
 }
 
 simpletest_script_init();
@@ -38,7 +42,7 @@ if ($args['execute-test']) {
   simpletest_script_setup_database();
   simpletest_script_run_one_test($args['test-id'], $args['execute-test']);
   // Sub-process exited already; this is just for clarity.
-  exit;
+  exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
 }
 
 if ($args['list']) {
@@ -52,7 +56,7 @@ if ($args['list']) {
       echo " - $class\n";
     }
   }
-  exit;
+  exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
 }
 
 simpletest_script_setup_database(TRUE);
@@ -67,7 +71,7 @@ if ($args['clean']) {
   foreach ($messages['status'] as $text) {
     echo " - " . $text . "\n";
   }
-  exit;
+  exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
 }
 
 $test_list = simpletest_script_get_test_list();
@@ -82,7 +86,7 @@ for ($i = 0; $i < $args['repeat']; $i++) {
 }
 
 // Execute tests.
-simpletest_script_execute_batch($tests_to_run);
+$status = simpletest_script_execute_batch($tests_to_run);
 
 // Stop the timer.
 simpletest_script_reporter_timer_stop();
@@ -100,7 +104,7 @@ if (!$args['keep-results']) {
 }
 
 // Test complete, exit.
-exit;
+exit($status);
 
 /**
  * Print help text.
@@ -275,7 +279,7 @@ function simpletest_script_parse_args() {
       else {
         // Argument not found in list.
         simpletest_script_print_error("Unknown argument '$arg'.");
-        exit;
+        exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
       }
     }
     else {
@@ -288,7 +292,7 @@ function simpletest_script_parse_args() {
   // Validate the concurrency argument
   if (!is_numeric($args['concurrency']) || $args['concurrency'] <= 0) {
     simpletest_script_print_error("--concurrency must be a strictly positive integer.");
-    exit;
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
 
   return array($args, $count);
@@ -320,7 +324,7 @@ function simpletest_script_init() {
   else {
     simpletest_script_print_error('Unable to automatically determine the path to the PHP interpreter. Supply the --php command line argument.');
     simpletest_script_help();
-    exit();
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
 
   // Get URL from arguments.
@@ -406,7 +410,7 @@ function simpletest_script_setup_database($new = FALSE) {
     $info = parse_url($args['dburl']);
     if (!isset($info['scheme'], $info['host'], $info['path'])) {
       simpletest_script_print_error('Invalid --dburl. Minimum requirement: driver://host/database');
-      exit(1);
+      exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
     }
     $info += array(
       'user' => '',
@@ -441,7 +445,7 @@ function simpletest_script_setup_database($new = FALSE) {
   // If there is no default database connection for tests, we cannot continue.
   if (!isset($databases['default']['default'])) {
     simpletest_script_print_error('Missing default database connection for tests. Use --dburl to specify one.');
-    exit(1);
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
   Database::addConnectionInfo('default', 'default', $databases['default']['default']);
 
@@ -485,7 +489,7 @@ function simpletest_script_setup_database($new = FALSE) {
   }
   catch (\PDOException $e) {
     simpletest_script_print_error($databases['test-runner']['default']['driver'] . ': ' . $e->getMessage());
-    exit(1);
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
   if ($new && $sqlite) {
     require_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'simpletest') . '/simpletest.install';
@@ -499,7 +503,7 @@ function simpletest_script_setup_database($new = FALSE) {
   // Verify that the Simpletest database schema exists by checking one table.
   if (!$schema->tableExists('simpletest')) {
     simpletest_script_print_error('Missing Simpletest database schema. Either install Simpletest module or use the --sqlite parameter.');
-    exit(1);
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
 }
 
@@ -509,6 +513,8 @@ function simpletest_script_setup_database($new = FALSE) {
 function simpletest_script_execute_batch($test_classes) {
   global $args, $test_ids;
 
+  $total_status = SIMPLETEST_SCRIPT_EXIT_SUCCESS;
+
   // Multi-process execution.
   $children = array();
   while (!empty($test_classes) || !empty($children)) {
@@ -525,7 +531,10 @@ function simpletest_script_execute_batch($test_classes) {
       // Process phpunit tests immediately since they are fast and we don't need
       // to fork for them.
       if (is_subclass_of($test_class, '\PHPUnit_Framework_TestCase')) {
-        simpletest_script_run_phpunit($test_id, $test_class);
+        $phpunit_status = simpletest_script_run_phpunit($test_id, $test_class);
+        if ($phpunit_status > $total_status) {
+          $total_status = $phpunit_status;
+        }
         continue;
       }
 
@@ -535,7 +544,7 @@ function simpletest_script_execute_batch($test_classes) {
 
       if (!is_resource($process)) {
         echo "Unable to fork test process. Aborting.\n";
-        exit;
+        exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
       }
 
       // Register our new child.
@@ -556,7 +565,13 @@ function simpletest_script_execute_batch($test_classes) {
       if (empty($status['running'])) {
         // The child exited, unregister it.
         proc_close($child['process']);
-        if ($status['exitcode']) {
+        if ($status['exitcode'] == SIMPLETEST_SCRIPT_EXIT_FAILURE) {
+          if ($status['exitcode'] > $total_status) {
+            $total_status = $status['exitcode'];
+          }
+        }
+        elseif ($status['exitcode']) {
+          $total_status = $status['exitcode'];
           echo 'FATAL ' . $child['class'] . ': test runner returned a non-zero error code (' . $status['exitcode'] . ').' . "\n";
           if ($args['die-on-fail']) {
             list($db_prefix, ) = simpletest_last_test_get($child['test_id']);
@@ -577,13 +592,14 @@ function simpletest_script_execute_batch($test_classes) {
       }
     }
   }
+  return $total_status;
 }
 
 /**
  * Run a group of phpunit tests.
  */
 function simpletest_script_run_phpunit($test_id, $class) {
-  $results = simpletest_run_phpunit_tests($test_id, array($class));
+  $results = simpletest_run_phpunit_tests($test_id, array($class), $status);
   simpletest_process_phpunit_results($results);
 
   // Map phpunit results to a data structure we can pass to
@@ -618,6 +634,7 @@ function simpletest_script_run_phpunit($test_id, $class) {
   foreach ($summaries as $class => $summary) {
     simpletest_script_reporter_display_summary($class, $summary);
   }
+  return $status;
 }
 
 /**
@@ -644,13 +661,16 @@ function simpletest_script_run_one_test($test_id, $test_class) {
     simpletest_script_reporter_display_summary($test_class, $test->results);
 
     // Finished, kill this runner.
-    exit(0);
+    if ($test->results['#fail'] || $test->results['#exception']) {
+      exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+    }
+    exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
   }
   // DrupalTestCase::run() catches exceptions already, so this is only reached
   // when an exception is thrown in the wrapping test runner environment.
   catch (Exception $e) {
     echo (string) $e;
-    exit(1);
+    exit(SIMPLETEST_SCRIPT_EXIT_EXCEPTION);
   }
 }
 
@@ -797,7 +817,7 @@ function simpletest_script_get_test_list() {
           }
           simpletest_script_print_error('Test class not found: ' . $class_name);
           simpletest_script_print_alternatives($class_name, $all_classes, 6);
-          exit(1);
+          exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
         }
       }
     }
@@ -806,7 +826,7 @@ function simpletest_script_get_test_list() {
       foreach ($args['test_names'] as $file) {
         if (!file_exists($file)) {
           simpletest_script_print_error('File not found: ' . $file);
-          exit;
+          exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
         }
         $content = file_get_contents($file);
         // Extract a potential namespace.
@@ -839,7 +859,7 @@ function simpletest_script_get_test_list() {
         else {
           simpletest_script_print_error('Test group not found: ' . $group_name);
           simpletest_script_print_alternatives($group_name, array_keys($groups));
-          exit(1);
+          exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
         }
       }
     }
@@ -847,7 +867,7 @@ function simpletest_script_get_test_list() {
 
   if (empty($test_list)) {
     simpletest_script_print_error('No valid tests were specified.');
-    exit;
+    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
   }
   return $test_list;
 }