diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index d66d2a9..cb4785f 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -793,7 +793,6 @@ protected function setUp() {
       $modules = array_unique($modules);
       $success = \Drupal::moduleHandler()->install($modules, TRUE);
       $this->assertTrue($success, t('Enabled modules: %modules', array('%modules' => implode(', ', $modules))));
-      $this->rebuildContainer();
     }
 
     // Reset/rebuild all data structures after enabling the modules.
@@ -960,6 +959,10 @@ protected function resetAll() {
     // Reset static variables and reload permissions.
     $this->refreshVariables();
     $this->checkPermissions(array(), TRUE);
+
+    // Make sure the url generator has a request object, otherwise calls to
+    // $this->drupalGet() will fail.
+    $this->prepareRequestForGenerator();
   }
 
   /**