diff -u b/core/modules/migrate/tests/src/MigrateSqlSourceTestCase.php b/core/modules/migrate/tests/src/MigrateSqlSourceTestCase.php
--- b/core/modules/migrate/tests/src/MigrateSqlSourceTestCase.php
+++ b/core/modules/migrate/tests/src/MigrateSqlSourceTestCase.php
@@ -79,7 +79,7 @@
       ->method('getHighwater')
       ->will($this->returnValue(static::ORIGINAL_HIGHWATER));
     // Need the test class, not the original because we need a setDatabase method. This is not pretty :/
-    $plugin_class  = preg_replace('/^(Drupal\\\\\w+\\\\)Plugin\\\\migrate(\\\\source(\\\\.+)?\\\\)([^\\\\]+)$/', '\1Tests\2Test\4', static::PLUGIN_CLASS);
+    $plugin_class  = preg_replace('/^Drupal\\\\(\w+)\\\\Plugin\\\\migrate(\\\\source(\\\\.+)?\\\\)([^\\\\]+)$/', 'Drupal\\Tests\\\$1$2Test$4', static::PLUGIN_CLASS);
     $plugin = new $plugin_class($this->migrationConfiguration['source'], $this->migrationConfiguration['source']['plugin'], array(), $migration);
     $plugin->setDatabase($this->getDatabase($this->databaseContents + array('test_map' => array())));
     $plugin->setModuleHandler($module_handler);
diff -u b/core/modules/views/tests/src/Plugin/field/CounterTest.php b/core/modules/views/tests/src/Plugin/field/CounterTest.php
--- b/core/modules/views/tests/src/Plugin/field/CounterTest.php
+++ b/core/modules/views/tests/src/Plugin/field/CounterTest.php
@@ -12,7 +12,7 @@
 use Drupal\views\Entity\View;
 use Drupal\views\Plugin\views\field\Counter;
 use Drupal\views\ResultRow;
-use Drupal\Tests\views\ViewTestData;
+use Drupal\views\Tests\ViewTestData;
 
 /**
  * Tests the counter field plugin.
diff -u b/core/modules/views/tests/src/PluginBaseTest.php b/core/modules/views/tests/src/PluginBaseTest.php
--- b/core/modules/views/tests/src/PluginBaseTest.php
+++ b/core/modules/views/tests/src/PluginBaseTest.php
@@ -8,7 +8,7 @@
 namespace Drupal\Tests\views;
 
 use Drupal\Tests\UnitTestCase;
-use Drupal\Tests\views\TestHelperPlugin;
+use Drupal\views\Tests\TestHelperPlugin;
 
 /**
  * Tests code of the views plugin base class.
@@ -20,7 +20,7 @@
   /**
    * The test helper plugin to use for the tests.
    *
-   * @var \Drupal\Tests\views\TestHelperPlugin
+   * @var \Drupal\views\Tests\TestHelperPlugin
    */
   protected $testHelperPlugin;
 
diff -u b/core/modules/views/tests/src/ViewsDataHelperTest.php b/core/modules/views/tests/src/ViewsDataHelperTest.php
--- b/core/modules/views/tests/src/ViewsDataHelperTest.php
+++ b/core/modules/views/tests/src/ViewsDataHelperTest.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Utility\String;
 use Drupal\Tests\UnitTestCase;
 use Drupal\views\ViewsDataHelper;
+use Drupal\views\Tests\ViewTestData;
 
 /**
  * Tests the views data helper class.
diff -u b/core/modules/views/tests/src/ViewsDataTest.php b/core/modules/views/tests/src/ViewsDataTest.php
--- b/core/modules/views/tests/src/ViewsDataTest.php
+++ b/core/modules/views/tests/src/ViewsDataTest.php
@@ -10,6 +10,7 @@
 use Drupal\Core\Language\Language;
 use Drupal\Tests\UnitTestCase;
 use Drupal\views\ViewsData;
+use Drupal\views\Tests\ViewTestData;
 
 /**
  * Tests the fetching of views data.
only in patch2:
unchanged:
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -577,8 +577,7 @@ function simpletest_classloader_register() {
   foreach ($types as $type) {
     foreach ($extensions[$type] as $name => $uri) {
       drupal_classloader_register($name, dirname($uri));
-      $classloader->addPsr4('Drupal\\' . $name . '\\Tests\\', array(
-        DRUPAL_ROOT . '/' . dirname($uri) . '/tests/Drupal/' . $name . '/Tests',
+      $classloader->addPsr4('Drupal\\Tests\\' . $name . '\\', array(
         DRUPAL_ROOT . '/' . dirname($uri) . '/tests/src',
       ));
       // While being there, prime drupal_get_filename().
only in patch2:
unchanged:
--- a/core/tests/bootstrap.php
+++ b/core/tests/bootstrap.php
@@ -62,7 +62,7 @@ function drupal_phpunit_register_extension_dirs(Composer\Autoload\ClassLoader $l
     }
     if (is_dir($dir . '/tests/src')) {
       // Register the PSR-4 directory for PHPUnit test classes.
-      $loader->addPsr4('Drupal\\' . $extension . '\Tests\\', $dir . '/tests/src');
+      $loader->addPsr4('Drupal\\Tests\\' . $extension . '\\', $dir . '/tests/src');
     }
   }
 }