diff --git a/modules/system/system.test b/modules/system/system.test
index 95b4353..462ff3a 100644
--- a/modules/system/system.test
+++ b/modules/system/system.test
@@ -1130,6 +1130,8 @@ class PageNotFoundTestCase extends DrupalWebTestCase {
 
     $this->drupalGet($this->randomName(10));
     $this->assertText($node->title, 'Found the custom 404 page');
+
+    $this->fail('This is a test failure.');
   }
 }
 
diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
index a42215e..786ef27 100755
--- a/scripts/run-tests.sh
+++ b/scripts/run-tests.sh
@@ -8,16 +8,12 @@ define('SIMPLETEST_SCRIPT_COLOR_PASS', 32); // Green.
 define('SIMPLETEST_SCRIPT_COLOR_FAIL', 31); // Red.
 define('SIMPLETEST_SCRIPT_COLOR_EXCEPTION', 33); // Brown.
 
-define('SIMPLETEST_SCRIPT_EXIT_SUCCESS', 0);
-define('SIMPLETEST_SCRIPT_EXIT_FAILURE', 1);
-define('SIMPLETEST_SCRIPT_EXIT_EXCEPTION', 2);
-
 // Set defaults and get overrides.
 list($args, $count) = simpletest_script_parse_args();
 
 if ($args['help'] || $count == 0) {
   simpletest_script_help();
-  exit(($count == 0) ? SIMPLETEST_SCRIPT_EXIT_FAILURE : SIMPLETEST_SCRIPT_EXIT_SUCCESS);
+  exit;
 }
 
 if ($args['execute-test']) {
@@ -34,7 +30,7 @@ else {
 drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
 if (!module_exists('simpletest')) {
   simpletest_script_print_error("The simpletest module must be enabled before this script can run.");
-  exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+  exit;
 }
 
 if ($args['clean']) {
@@ -47,7 +43,7 @@ if ($args['clean']) {
   foreach ($messages as $text) {
     echo " - " . $text . "\n";
   }
-  exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
+  exit;
 }
 
 // Load SimpleTest files.
@@ -68,7 +64,7 @@ if ($args['list']) {
       echo " - " . $info['name'] . ' (' . $class . ')' . "\n";
     }
   }
-  exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
+  exit;
 }
 
 $test_list = simpletest_script_get_test_list();
@@ -82,7 +78,7 @@ simpletest_script_reporter_init();
 $test_id = db_insert('simpletest_test_id')->useDefaults(array('test_id'))->execute();
 
 // Execute tests.
-$status = simpletest_script_execute_batch($test_id, simpletest_script_get_test_list());
+simpletest_script_execute_batch($test_id, simpletest_script_get_test_list());
 
 // Retrieve the last database prefix used for testing and the last test class
 // that was run from. Use the information to read the lgo file in case any
@@ -104,7 +100,7 @@ if ($args['xml']) {
 simpletest_clean_results_table($test_id);
 
 // Test complete, exit.
-exit($status);
+exit;
 
 /**
  * Print help text.
@@ -229,7 +225,7 @@ function simpletest_script_parse_args() {
       else {
         // Argument not found in list.
         simpletest_script_print_error("Unknown argument '$arg'.");
-        exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+        exit;
       }
     }
     else {
@@ -242,7 +238,7 @@ function simpletest_script_parse_args() {
   // Validate the concurrency argument
   if (!is_numeric($args['concurrency']) || $args['concurrency'] <= 0) {
     simpletest_script_print_error("--concurrency must be a strictly positive integer.");
-    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+    exit;
   }
 
   return array($args, $count);
@@ -272,7 +268,7 @@ function simpletest_script_init($server_software) {
   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(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+    exit();
   }
 
   // Get URL from arguments.
@@ -317,8 +313,6 @@ function simpletest_script_init($server_software) {
 function simpletest_script_execute_batch($test_id, $test_classes) {
   global $args;
 
-  $total_status = SIMPLETEST_SCRIPT_EXIT_SUCCESS;
-
   // Multi-process execution.
   $children = array();
   while (!empty($test_classes) || !empty($children)) {
@@ -334,7 +328,7 @@ function simpletest_script_execute_batch($test_id, $test_classes) {
 
       if (!is_resource($process)) {
         echo "Unable to fork test process. Aborting.\n";
-        exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+        exit;
       }
 
       // Register our new child.
@@ -354,22 +348,13 @@ function simpletest_script_execute_batch($test_id, $test_classes) {
       if (empty($status['running'])) {
         // The child exited, unregister it.
         proc_close($child['process']);
-        if ($status['exitcode'] == SIMPLETEST_SCRIPT_EXIT_FAILURE) {
-          if ($status['exitcode'] > $total_status) {
-            $total_status = $status['exitcode'];
-          }
-        }
-        elseif ($status['exitcode']) {
-          $total_status = $status['exitcode'];
+        if ($status['exitcode']) {
           echo 'FATAL ' . $test_class . ': test runner returned a non-zero error code (' . $status['exitcode'] . ').' . "\n";
         }
-
-        // Remove this child.
         unset($children[$cid]);
       }
     }
   }
-  return $total_status;
 }
 
 /**
@@ -392,14 +377,11 @@ function simpletest_script_run_one_test($test_id, $test_class) {
     simpletest_script_print($info['name'] . ' ' . _simpletest_format_summary_line($test->results) . "\n", simpletest_script_color_code($status));
 
     // Finished, kill this runner.
-    if ($had_fails || $had_exceptions) {
-      exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
-    }
-    exit(SIMPLETEST_SCRIPT_EXIT_SUCCESS);
+    exit(0);
   }
   catch (Exception $e) {
     echo (string) $e;
-    exit(SIMPLETEST_SCRIPT_EXIT_EXCEPTION);
+    exit(1);
   }
 }
 
@@ -453,7 +435,7 @@ function simpletest_script_get_test_list() {
           }
           simpletest_script_print_error('Test class not found: ' . $test_class);
           simpletest_script_print_alternatives($test_class, $all_classes, 6);
-          exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+          exit(1);
         }
       }
     }
@@ -526,7 +508,7 @@ 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(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+          exit(1);
         }
       }
     }
@@ -534,7 +516,7 @@ function simpletest_script_get_test_list() {
 
   if (empty($test_list)) {
     simpletest_script_print_error('No valid tests were specified.');
-    exit(SIMPLETEST_SCRIPT_EXIT_FAILURE);
+    exit;
   }
   return $test_list;
 }