diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index 5eb5b26..dee1760 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -175,10 +175,8 @@ public function containerBuild(ContainerBuilder $container) {
         ->addArgument(new Reference('service_container'))
         ->addArgument(new Reference('settings'));
 
-      $container->register('state', 'Drupal\Core\KeyValueStore\KeyValueStoreInterface')
-        ->setFactoryService(new Reference('keyvalue'))
-        ->setFactoryMethod('get')
-        ->addArgument('state');
+      $container->register('state', 'Drupal\Core\KeyValueStore\State')
+        ->addArgument(new Reference('keyvalue'));
     }
 
     if ($container->hasDefinition('path_processor_alias')) {
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 6dca5de..e26b53b 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -3443,6 +3443,7 @@ protected function assertNoResponse($code, $message = '', $group = 'Browser') {
    *   TRUE on pass, FALSE on fail.
    */
   protected function assertMail($name, $value = '', $message = '', $group = 'E-mail') {
+    \Drupal::state()->resetCache();
     $captured_emails = \Drupal::state()->get('system.test_email_collector') ?: array();
     $email = end($captured_emails);
     return $this->assertTrue($email && isset($email[$name]) && $email[$name] == $value, $message, $group);