diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index d7adb65..3996210 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -323,12 +323,10 @@ function simpletest_test_get_all() {
     else {
       // Select all PSR-0 classes in the Tests namespace of all modules.
       $classes = array();
-      $module_data = system_rebuild_module_data();
-      $all_data = $module_data + system_rebuild_theme_data();
-      $all_data += drupal_system_listing('/\.profile$/', 'profiles', 'name');
+      $all_data = array('system' => (object)array('uri' => 'core/modules/system/system.module'));
       foreach ($all_data as $name => $data) {
         // Build directory in which the test files would reside.
-        $tests_dir = DRUPAL_ROOT . '/' . dirname($data->uri) . '/lib/Drupal/' . $name . '/Tests';
+        $tests_dir = DRUPAL_ROOT . '/' . dirname($data->uri) . '/lib/Drupal/' . $name . '/Tests/Upgrade';
         // Scan it for test files if it exists.
         if (is_dir($tests_dir)) {
           $files = file_scan_directory($tests_dir, '/.*\.php/');
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php
index c4dda65..150c282 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/UpgradePathTestBase.php
@@ -203,13 +203,15 @@ protected function refreshVariables() {
   protected function performUpgrade($register_errors = TRUE) {
 
     // Load the first update screen.
-    $this->getUpdatePhp();
+    $out = $this->getUpdatePhp();
     if (!$this->assertResponse(200)) {
+      debug($out, 'response');
       throw new Exception('Initial GET to update.php did not return HTTP 200 status.');
     }
 
     // Ensure that the first update screen appeared correctly.
     if (!$this->assertFieldByXPath('//input[@type="submit"]')) {
+      debug($out, 'response');
       throw new Exception('An error was encountered during the first access to update.php.');
     }
 
@@ -219,21 +221,23 @@ protected function performUpgrade($register_errors = TRUE) {
     $this->rebuildContainer();
 
     // Continue.
-    $this->drupalPost(NULL, array(), t('Continue'));
+    $out = $this->drupalPost(NULL, array(), t('Continue'));
     if (!$this->assertResponse(200)) {
+      debug($out, 'response');
       throw new Exception('POST to continue update.php did not return HTTP 200 status.');
     }
 
     // The test should pass if there are no pending updates.
     $content = $this->drupalGetContent();
     if (strpos($content, t('No pending updates.')) !== FALSE) {
+      debug(strip_tags($out), 'response');
       $this->pass('No pending updates and therefore no upgrade process to test.');
       $this->pendingUpdates = FALSE;
       return TRUE;
     }
 
     // Go!
-    $this->drupalPost(NULL, array(), t('Apply pending updates'));
+    $out = $this->drupalPost(NULL, array(), t('Apply pending updates'));
     if (!$this->assertResponse(200)) {
       throw new Exception('POST to update.php to apply pending updates did not return HTTP 200 status.');
     }
@@ -247,15 +251,18 @@ protected function performUpgrade($register_errors = TRUE) {
       }
     }
     if (!empty($this->upgradeErrors)) {
+      debug(strip_tags($out), 'response');
       // Upgrade failed, the installation might be in an inconsistent state,
       // don't process.
       throw new Exception('Errors during update process.');
     }
 
     // Check if there still are pending updates.
-    $this->getUpdatePhp();
+    $out_pending = $this->getUpdatePhp();
     $this->drupalPost(NULL, array(), t('Continue'));
     if (!$this->assertText(t('No pending updates.'), 'No pending updates at the end of the update process.')) {
+      debug(strip_tags($out), 'response before');
+      debug(strip_tags($out_pending), 'response pending');
       throw new Exception('update.php still shows pending updates after execution.');
     }