diff --git a/core/modules/simpletest/src/Tests/KernelTestBaseTest.php b/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
index 1537393876c..34d78f19ea2 100644
--- a/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
+++ b/core/modules/simpletest/src/Tests/KernelTestBaseTest.php
@@ -29,6 +29,15 @@ class KernelTestBaseTest extends KernelTestBase {
     );
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $original_container = \Drupal::getContainer();
+    parent::setUp();
+    $this->assertNotIdentical(\Drupal::getContainer(), $original_container, 'KernelTestBase test creates a new container.');
+  }
+
   /**
    * Tests expected behavior of setUp().
    */
diff --git a/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
index a0e57381d16..b2fffb36d60 100755
--- a/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -74,7 +74,9 @@ services:
 EOD;
       file_put_contents($this->siteDirectory . '/testing.services.yml', $yaml);
 
+      $original_container = \Drupal::getContainer();
       parent::setUp();
+      $this->assertNotIdentical(\Drupal::getContainer(), $original_container, 'WebTestBase test creates a new container.');
       // Create and log in an admin user.
       $this->drupalLogin($this->drupalCreateUser(array('administer unit tests')));
     }