Merge branch '6.0' into 6.1

* 6.0:
  fix merge
  do not use mocks in tests when not necessary
  [Mailer] Missing import in first example
  [Security] Add test case for user not found
  [SecurityBundle] Use config's secret in remember-me signatures

Author: xabbuh

Tests/Authenticator/Passport/Badge/UserBadgeTest.php

@@ -0,0 +1,26 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Http\Tests\Authenticator\Passport\Badge;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Security\Core\Exception\UserNotFoundException;
+use Symfony\Component\Security\Http\Authenticator\Passport\Badge\UserBadge;
+
+class UserBadgeTest extends TestCase
+{
+    public function testUserNotFound()
+    {
+        $badge = new UserBadge('dummy', function () { return null; });
+        $this->expectException(UserNotFoundException::class);
+        $badge->getUser();
+    }
+}