reverted:
--- b/src/Tests/DiffRevisionTest.php
+++ a/src/Tests/DiffRevisionTest.php
@@ -3,8 +3,8 @@
 namespace Drupal\diff\Tests;
 
 use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\system\Tests\Menu\AssertBreadcrumbTrait;
 use Drupal\Tests\diff\Functional\CoreVersionUiTestTrait;
-use Drupal\Tests\system\Functional\Menu\AssertBreadcrumbTrait;
 
 /**
  * Tests the diff revisions overview.
diff -u b/src/Tests/DiffViewsTest.php b/src/Tests/DiffViewsTest.php
--- b/src/Tests/DiffViewsTest.php
+++ b/src/Tests/DiffViewsTest.php
@@ -8,6 +8,4 @@
 use Drupal\Tests\views\Functional\ViewTestBase;
 
-//use Drupal\views\Tests\ViewTestBase;
-
 /**
  * Tests the diff views integration.