diff --git a/core/modules/aggregator/aggregator.module b/core/modules/aggregator/aggregator.module
index bd0c6c1..ff4773f 100644
--- a/core/modules/aggregator/aggregator.module
+++ b/core/modules/aggregator/aggregator.module
@@ -456,10 +456,12 @@ function aggregator_save_category($edit) {
         ->condition('cid', $edit['cid'])
         ->execute();
       // Make sure there is no active block for this category.
-      db_delete('block')
-        ->condition('module', 'aggregator')
-        ->condition('delta', 'category-' . $edit['cid'])
-        ->execute();
+      if (module_exists('block')) {
+        db_delete('block')
+          ->condition('module', 'aggregator')
+          ->condition('delta', 'category-' . $edit['cid'])
+          ->execute();
+      }
       $edit['title'] = '';
       $op = 'delete';
     }
@@ -521,10 +523,12 @@ function aggregator_save_feed($edit) {
       ->condition('fid', $edit['fid'])
       ->execute();
     // Make sure there is no active block for this feed.
-    db_delete('block')
-      ->condition('module', 'aggregator')
-      ->condition('delta', 'feed-' . $edit['fid'])
-      ->execute();
+    if (module_exists('block')) {
+      db_delete('block')
+        ->condition('module', 'aggregator')
+        ->condition('delta', 'feed-' . $edit['fid'])
+        ->execute();
+    }
   }
   elseif (!empty($edit['title'])) {
     $edit['fid'] = db_insert('aggregator_feed')
diff --git a/core/modules/aggregator/aggregator.test b/core/modules/aggregator/aggregator.test
index 522129f..bacabb1 100644
--- a/core/modules/aggregator/aggregator.test
+++ b/core/modules/aggregator/aggregator.test
@@ -7,7 +7,22 @@
 
 class AggregatorTestCase extends DrupalWebTestCase {
   function setUp() {
-    parent::setUp('aggregator', 'aggregator_test');
+    parent::setUp(array('node', 'aggregator', 'aggregator_test'));
+
+    // Create an Article node type.
+    $type = array(
+      'type' => 'article',
+      'name' => t('Article'),
+      'base' => 'node_content',
+      'custom' => 1,
+      'modified' => 1,
+      'locked' => 0,
+    );
+    $type = node_type_set_defaults($type);
+    node_type_save($type);
+    node_add_body_field($type);
+    $this->resetAll();
+
     $web_user = $this->drupalCreateUser(array('administer news feeds', 'access news feeds', 'create article content'));
     $this->drupalLogin($web_user);
   }
diff --git a/core/modules/block/block.test b/core/modules/block/block.test
index dbd7dc4..50f3246 100644
--- a/core/modules/block/block.test
+++ b/core/modules/block/block.test
@@ -465,6 +465,10 @@ class BlockAdminThemeTestCase extends DrupalWebTestCase {
     );
   }
 
+  function setUp() {
+    parent::setUp(array('block'));
+  }
+
   /**
    * Check for the accessibility of the admin theme on the  block admin page.
    */
@@ -474,13 +478,13 @@ class BlockAdminThemeTestCase extends DrupalWebTestCase {
     $this->drupalLogin($admin_user);
 
     // Ensure that access to block admin page is denied when theme is disabled.
-    $this->drupalGet('admin/structure/block/list/stark');
+    $this->drupalGet('admin/structure/block/list/bartik');
     $this->assertResponse(403, t('The block admin page for a disabled theme can not be accessed'));
 
     // Enable admin theme and confirm that tab is accessible.
-    $edit['admin_theme'] = 'stark';
+    $edit['admin_theme'] = 'bartik';
     $this->drupalPost('admin/appearance', $edit, t('Save configuration'));
-    $this->drupalGet('admin/structure/block/list/stark');
+    $this->drupalGet('admin/structure/block/list/bartik');
     $this->assertResponse(200, t('The block admin page for the admin theme can be accessed'));
   }
 }
diff --git a/core/modules/simpletest/drupal_web_test_case.php b/core/modules/simpletest/drupal_web_test_case.php
index 0edd3fd..aa6ea4d 100644
--- a/core/modules/simpletest/drupal_web_test_case.php
+++ b/core/modules/simpletest/drupal_web_test_case.php
@@ -765,7 +765,7 @@ class DrupalWebTestCase extends DrupalTestCase {
    *
    * @var string
    */
-  protected $profile = 'standard';
+  protected $profile = 'testing';
 
   /**
    * The URL currently loaded in the internal browser.
diff --git a/core/modules/simpletest/tests/ajax.test b/core/modules/simpletest/tests/ajax.test
index 9a76b96..00eb164 100644
--- a/core/modules/simpletest/tests/ajax.test
+++ b/core/modules/simpletest/tests/ajax.test
@@ -58,8 +58,6 @@ class AJAXTestCase extends DrupalWebTestCase {
  * Tests primary Ajax framework functions.
  */
 class AJAXFrameworkTestCase extends AJAXTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'AJAX framework',
diff --git a/core/modules/simpletest/tests/common.test b/core/modules/simpletest/tests/common.test
index 8936808..c66e9c3 100644
--- a/core/modules/simpletest/tests/common.test
+++ b/core/modules/simpletest/tests/common.test
@@ -2196,11 +2196,6 @@ class ParseInfoFilesTestCase extends DrupalWebTestCase {
  * Tests for the drupal_system_listing() function.
  */
 class DrupalSystemListingTestCase extends DrupalWebTestCase {
-  /**
-   * Use the testing profile; this is needed for testDirectoryPrecedence().
-   */
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Drupal system listing',
diff --git a/core/modules/simpletest/tests/database_test.test b/core/modules/simpletest/tests/database_test.test
index 6e55fbd..164ddce 100644
--- a/core/modules/simpletest/tests/database_test.test
+++ b/core/modules/simpletest/tests/database_test.test
@@ -16,8 +16,6 @@ class FakeRecord { }
  * here.
  */
 class DatabaseTestCase extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   function setUp() {
     parent::setUp('database_test');
 
diff --git a/core/modules/simpletest/tests/form.test b/core/modules/simpletest/tests/form.test
index 94dfa87..504a111 100644
--- a/core/modules/simpletest/tests/form.test
+++ b/core/modules/simpletest/tests/form.test
@@ -372,8 +372,6 @@ class FormsTestCase extends DrupalWebTestCase {
  * Tests building and processing of core form elements.
  */
 class FormElementTestCase extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Element processing',
diff --git a/core/modules/simpletest/tests/menu.test b/core/modules/simpletest/tests/menu.test
index d0612ac..df9b80c 100644
--- a/core/modules/simpletest/tests/menu.test
+++ b/core/modules/simpletest/tests/menu.test
@@ -647,9 +647,6 @@ class MenuRouterTestCase extends DrupalWebTestCase {
  * Tests for menu links.
  */
 class MenuLinksUnitTestCase extends DrupalWebTestCase {
-  // Use the lightweight testing profile for this test.
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Menu links',
@@ -1520,12 +1517,7 @@ class MenuTrailTestCase extends MenuWebTestCase {
   }
 
   function setUp() {
-    $modules = func_get_args();
-    if (isset($modules[0]) && is_array($modules[0])) {
-      $modules = $modules[0];
-    }
-    $modules[] = 'menu_test';
-    parent::setUp($modules);
+    parent::setUp(array('block', 'menu_test'));
     $this->admin_user = $this->drupalCreateUser(array('administer site configuration', 'access administration pages'));
     $this->drupalLogin($this->admin_user);
 
diff --git a/core/modules/simpletest/tests/password.test b/core/modules/simpletest/tests/password.test
index e0139e9..2797786 100644
--- a/core/modules/simpletest/tests/password.test
+++ b/core/modules/simpletest/tests/password.test
@@ -9,8 +9,6 @@
  * Unit tests for password hashing API.
  */
 class PasswordHashingTest extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Password hashing',
diff --git a/core/modules/simpletest/tests/theme.test b/core/modules/simpletest/tests/theme.test
index 6fb6b3b..7649e3d 100644
--- a/core/modules/simpletest/tests/theme.test
+++ b/core/modules/simpletest/tests/theme.test
@@ -9,8 +9,6 @@
  * Unit tests for the Theme API.
  */
 class ThemeUnitTest extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Theme API',
@@ -178,8 +176,6 @@ class ThemeTableUnitTest extends DrupalWebTestCase {
  * Tests for common theme functions.
  */
 class ThemeFunctionsTestCase extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Theme functions',
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 6dca80b..117bf5e 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -1487,7 +1487,7 @@ function system_site_information_settings() {
   $form['front_page']['site_frontpage'] = array(
     '#type' => 'textfield',
     '#title' => t('Default front page'),
-    '#default_value' => (variable_get('site_frontpage')!='node'?drupal_get_path_alias(variable_get('site_frontpage', 'node')):''),
+    '#default_value' => (variable_get('site_frontpage')!='user'?drupal_get_path_alias(variable_get('site_frontpage', 'user')):''),
     '#size' => 40,
     '#description' => t('Optionally, specify a relative URL to display as the front page.  Leave blank to display the default content feed.'),
     '#field_prefix' => url(NULL, array('absolute' => TRUE)) . (variable_get('clean_url', 0) ? '' : '?q='),
@@ -1536,7 +1536,7 @@ function system_site_information_settings_validate($form, &$form_state) {
   // Check for empty front page path.
   if (empty($form_state['values']['site_frontpage'])) {
     // Set to default "node".
-    form_set_value($form['front_page']['site_frontpage'], 'node', $form_state);
+    form_set_value($form['front_page']['site_frontpage'], 'user', $form_state);
   }
   else {
     // Get the normal path of the front page.
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 625be0a..756f375 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2036,8 +2036,12 @@ function system_user_timezone(&$form, &$form_state) {
 function system_block_info() {
   $blocks['main'] = array(
     'info' => t('Main page content'),
-     // Cached elsewhere.
+    // Cached elsewhere.
     'cache' => DRUPAL_NO_CACHE,
+    // Automatically try to assign the main content to the "content" region, in
+    // case such a region exists.
+    'region' => 'content',
+    'status' => 1,
   );
   $blocks['powered-by'] = array(
     'info' => t('Powered by Drupal'),
diff --git a/core/modules/system/system.test b/core/modules/system/system.test
index 4e3761d..c767254 100644
--- a/core/modules/system/system.test
+++ b/core/modules/system/system.test
@@ -130,8 +130,6 @@ class ModuleTestCase extends DrupalWebTestCase {
  * Test module enabling/disabling functionality.
  */
 class EnableDisableTestCase extends ModuleTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Enable/disable modules',
@@ -885,10 +883,13 @@ class AccessDeniedTestCase extends DrupalWebTestCase {
   }
 
   function setUp() {
-    parent::setUp();
+    parent::setUp(array('block'));
 
     // Create an administrative user.
     $this->admin_user = $this->drupalCreateUser(array('access administration pages', 'administer site configuration', 'administer blocks'));
+
+    user_role_grant_permissions(DRUPAL_ANONYMOUS_RID, array('access user profiles'));
+    user_role_grant_permissions(DRUPAL_AUTHENTICATED_RID, array('access user profiles'));
   }
 
   function testAccessDenied() {
@@ -896,34 +897,34 @@ class AccessDeniedTestCase extends DrupalWebTestCase {
     $this->assertText(t('Access denied'), t('Found the default 403 page'));
     $this->assertResponse(403);
 
+    // Use a custom 403 page.
     $this->drupalLogin($this->admin_user);
     $edit = array(
-      'title' => $this->randomName(10),
-      'body' => array(LANGUAGE_NONE => array(array('value' => $this->randomName(100)))),
+      'site_403' => 'user/' . $this->admin_user->uid,
     );
-    $node = $this->drupalCreateNode($edit);
-
-    // Use a custom 403 page.
-    $this->drupalPost('admin/config/system/site-information', array('site_403' => 'node/' . $node->nid), t('Save configuration'));
+    $this->drupalPost('admin/config/system/site-information', $edit, t('Save configuration'));
 
-    $this->drupalLogout();
-    $this->drupalGet('admin');
-    $this->assertText($node->title, t('Found the custom 403 page'));
+    // Enable the user login block.
+    $edit = array(
+      'blocks[user_login][region]' => 'sidebar_first',
+    );
+    $this->drupalPost('admin/structure/block', $edit, t('Save blocks'));
 
     // Logout and check that the user login block is shown on custom 403 pages.
     $this->drupalLogout();
-
     $this->drupalGet('admin');
-    $this->assertText($node->title, t('Found the custom 403 page'));
+    $this->assertText($this->admin_user->name, t('Found the custom 403 page'));
     $this->assertText(t('User login'), t('Blocks are shown on the custom 403 page'));
 
     // Log back in and remove the custom 403 page.
     $this->drupalLogin($this->admin_user);
-    $this->drupalPost('admin/config/system/site-information', array('site_403' => ''), t('Save configuration'));
+    $edit = array(
+      'site_403' => '',
+    );
+    $this->drupalPost('admin/config/system/site-information', $edit, t('Save configuration'));
 
     // Logout and check that the user login block is shown on default 403 pages.
     $this->drupalLogout();
-
     $this->drupalGet('admin');
     $this->assertText(t('Access denied'), t('Found the default 403 page'));
     $this->assertResponse(403);
@@ -950,9 +951,6 @@ class AccessDeniedTestCase extends DrupalWebTestCase {
 class PageNotFoundTestCase extends DrupalWebTestCase {
   protected $admin_user;
 
-  /**
-   * Implement getInfo().
-   */
   public static function getInfo() {
     return array(
       'name' => '404 functionality',
@@ -961,32 +959,29 @@ class PageNotFoundTestCase extends DrupalWebTestCase {
     );
   }
 
-  /**
-   * Implement setUp().
-   */
   function setUp() {
     parent::setUp();
 
     // Create an administrative user.
     $this->admin_user = $this->drupalCreateUser(array('administer site configuration'));
-    $this->drupalLogin($this->admin_user);
+
+    user_role_grant_permissions(DRUPAL_ANONYMOUS_RID, array('access user profiles'));
+    user_role_grant_permissions(DRUPAL_AUTHENTICATED_RID, array('access user profiles'));
   }
 
   function testPageNotFound() {
+    $this->drupalLogin($this->admin_user);
     $this->drupalGet($this->randomName(10));
     $this->assertText(t('Page not found'), t('Found the default 404 page'));
 
+    // Use a custom 404 page.
     $edit = array(
-      'title' => $this->randomName(10),
-      'body' => array(LANGUAGE_NONE => array(array('value' => $this->randomName(100)))),
+      'site_404' => 'user/' . $this->admin_user->uid,
     );
-    $node = $this->drupalCreateNode($edit);
-
-    // Use a custom 404 page.
-    $this->drupalPost('admin/config/system/site-information', array('site_404' => 'node/' . $node->nid), t('Save configuration'));
+    $this->drupalPost('admin/config/system/site-information', $edit, t('Save configuration'));
 
     $this->drupalGet($this->randomName(10));
-    $this->assertText($node->title, t('Found the custom 404 page'));
+    $this->assertText($this->admin_user->name, t('Found the custom 404 page'));
   }
 }
 
@@ -1447,8 +1442,6 @@ class FrontPageTestCase extends DrupalWebTestCase {
 }
 
 class SystemBlockTestCase extends DrupalWebTestCase {
-  protected $profile = 'testing';
-
   public static function getInfo() {
     return array(
       'name' => 'Block functionality',