diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index 5f0183a..ec34c53 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -30,6 +30,8 @@
  *
  * @see \Drupal\simpletest\KernelTestBase::$modules
  * @see \Drupal\simpletest\KernelTestBase::enableModules()
+ *
+ * @ingroup testing
  */
 abstract class KernelTestBase extends UnitTestBase {
 
diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index 765f9e4..8c48e37 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -725,7 +725,7 @@
  * PHPUnit tests for classes are written using the industry-standard PHPUnit
  * framework. Use a PHPUnit test to test functionality of a class if the Drupal
  * environment (database, settings, etc.) and web browser are not needed for the
- * test, or if the Drupal environment can be replaced by a "mocking" class. To
+ * test, or if the Drupal environment can be replaced by a "mock" object. To
  * write a PHPUnit test:
  * - Define a class that extends \Drupal\Tests\UnitTestCase.
  * - The class name needs to end in the word Test.
@@ -753,17 +753,15 @@
  * - For functional tests of the web output of Drupal, define a class that
  *   extends \Drupal\simpletest\WebTestBase, which contains an internal web
  *   browser and defines many helpful test assertion methods that you can use
- *   in your tests. You can define additional modules to be enabled by
- *   overriding the $modules member variable -- keep in mind that by default,
- *   WebTestBase uses a "testing" install profile, with a minimal set of
- *   modules enabled.
+ *   in your tests. You can specify modules to be enabled by defining a
+ *   $modules member variable -- keep in mind that by default, WebTestBase uses
+ *   a "testing" install profile, with a minimal set of modules enabled.
  * - For functional tests that do not test web output, define a class that
- *   extends \Drupal\simpletest\DrupalUnitTestBase. This class is much faster
+ *   extends \Drupal\simpletest\KernelTestBase. This class is much faster
  *   than WebTestBase, because instead of making a full install of Drupal, it
  *   uses an in-memory pseudo-installation (similar to what the installer and
  *   update scripts use). To use this test class, you will need to create the
  *   database tables you need and install needed modules manually.
- * - The class name needs to end in the word Test.
  * - The namespace must be a subspace/subdirectory of \Drupal\yourmodule\Tests,
  *   where yourmodule is your module's machine name.
  * - The test class file must be named and placed under the yourmodule/src/Tests
@@ -792,7 +790,8 @@
  * @link https://drupal.org/project/drush Drush @endlink, or from the Testing
  * module user interface.
  *
- * PHPUnit tests can also be run from the PHPUnit framework.
+ * PHPUnit tests can also be run from the command line, using the PHPUnit
+ * framework. See https://drupal.org/node/2116263 for more information.
  * @}
  */