diff -u b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportUITest.php
@@ -119,7 +119,7 @@
    * Tests verification of site UUID before importing configuration.
    */
   function testImportSiteUuidValidation() {
-    $staging = $this->container->get('config.storage.staging');
+    $staging = \Drupal::service('config.storage.staging');
     // Create updated configuration object.
     $config_data = \Drupal::config('system.site')->get();
     // Generate a new site UUID.
diff -u b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImporterTest.php
@@ -100,7 +100,7 @@
    * Tests verification of site UUID before importing configuration.
    */
   function testSiteUuidValidate() {
-    $staging = $this->container->get('config.storage.staging');
+    $staging = \Drupal::service('config.storage.staging');
     // Create updated configuration object.
     $config_data = \Drupal::config('system.site')->get();
     // Generate a new site UUID.
diff -u b/core/modules/system/config/schema/system.schema.yml b/core/modules/system/config/schema/system.schema.yml
--- b/core/modules/system/config/schema/system.schema.yml
+++ b/core/modules/system/config/schema/system.schema.yml
@@ -40,5 +40,4 @@
       label: 'Site UUID'
 
-
 system.maintenance:
   type: mapping
only in patch2:
unchanged:
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php
@@ -42,6 +42,13 @@ class ConfigExportImportUITest extends WebTestBase {
   protected $admin_role;
 
   /**
+   * The site UUID.
+   *
+   * @var string
+   */
+  protected $siteUuid;
+
+  /**
    * Sort methods alphabetically in order to allow for a predictable sequence.
    */
   const SORT_METHODS = TRUE;
@@ -77,6 +84,7 @@ function testExport() {
       ->save();
     $this->drupalPostForm('admin/config/development/configuration/full/export', array(), 'Export');
     $this->tarball = $this->drupalGetContent();
+    $this->siteUuid = \Drupal::config('system.site')->get('uuid');
   }
 
   /**
@@ -104,6 +112,8 @@ function testImport() {
    *   The name of the tarball containing the configuration to be imported.
    */
   protected function doImport($filename) {
+    // Ensure site uuids match so that import works.
+    \Drupal::config('system.site')->set('uuid', $this->siteUuid)->save();
     $this->assertNotEqual($this->slogan, \Drupal::config('system.site')->get('slogan'));
     $this->drupalPostForm('admin/config/development/configuration/full/import', array('files[import_tarball]' => $filename), 'Upload');
     $this->drupalPostForm(NULL, array(), 'Import all');