diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index b24f12a..c21f43e 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -724,7 +724,7 @@ protected function initializeContainer($rebuild = FALSE) {
     // new session into the master request if one was present before.
     if (($request_stack = $this->container->get('request_stack', ContainerInterface::NULL_ON_INVALID_REFERENCE))) {
       if ($request = $request_stack->getMasterRequest()) {
-        if (!$request->hasSession()) {
+        if ($request->hasSession()) {
           $request->setSession($this->container->get('session'));
         }
       }
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 398909f..d6cec81 100644
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -36,6 +36,7 @@
 $kernel->loadLegacyIncludes();;
 
 if ($args['execute-test']) {
+  $kernel->prepareLegacyRequest($request);
   simpletest_script_setup_database();
   simpletest_script_run_one_test($args['test-id'], $args['execute-test']);
   // Sub-process exited already; this is just for clarity.