diff --git a/core/modules/simpletest/src/TestDiscovery.php b/core/modules/simpletest/src/TestDiscovery.php
index 2ae84b2..3bc9ffa 100644
--- a/core/modules/simpletest/src/TestDiscovery.php
+++ b/core/modules/simpletest/src/TestDiscovery.php
@@ -97,7 +97,7 @@ public function registerTestNamespaces() {
       // Add Simpletest test namespace.
       $this->testNamespaces["Drupal\\$name\\Tests\\"][] = "$base_path/src/Tests";
 
-      // Add PHPUnit test namespaces.
+      // Add PHPUnit test namespace.
       $this->testNamespaces["Drupal\\Tests\\$name\\"][] = "$base_path/tests/src";
     }
 
diff --git a/core/modules/simpletest/tests/src/Traits/TestTrait.php b/core/modules/simpletest/tests/src/Traits/TestTrait.php
index ddabba7..1bd1738 100644
--- a/core/modules/simpletest/tests/src/Traits/TestTrait.php
+++ b/core/modules/simpletest/tests/src/Traits/TestTrait.php
@@ -3,18 +3,22 @@
 /**
  * @file
  * Contains \Drupal\Tests\simpletest\TestTrait.
- *
- * A nothing trait, but declared in the Drupal\Tests namespace.
- *
- * @see Drupal\Tests\simpletest\Unit\TestTraitAccessTest
  */
 
 namespace Drupal\Tests\simpletest\Traits;
 
-
+/**
+ * Provides a trait declared in the Drupal\Tests namespace.
+ *
+ * We declare the trait here to make sure that traits found in
+ * the Drupal\Tests namespace are visible to our test runner.
+ *
+ * @see Drupal\Tests\simpletest\Unit\TestTraitAccessTest
+ */
 trait TestTrait {
   /**
-   * Random string for a not very interesting trait.
+   * Test string for our not very interesting trait.
+   *
    * @var string
    */
   protected $stuff = 'stuff';
@@ -23,9 +27,10 @@
    * Return a test string to a trait user.
    *
    * @return string
-   *  Just a random sort of string.
+   *   A test string.
    */
   protected function getStuff() {
     return $this->stuff;
   }
+
 }
diff --git a/core/modules/simpletest/tests/src/Unit/TraitAccessTest.php b/core/modules/simpletest/tests/src/Unit/TraitAccessTest.php
index d699656..46fe07d 100644
--- a/core/modules/simpletest/tests/src/Unit/TraitAccessTest.php
+++ b/core/modules/simpletest/tests/src/Unit/TraitAccessTest.php
@@ -12,7 +12,7 @@
 use Drupal\Tests\simpletest\Traits\TestTrait;
 
 /**
- * Tests if a PHPUnit test can find a trait in its own namespace.
+ * Tests if a PHPUnit test can find a trait under the Drupal\Tests namespace.
  *
  * @group simpletest
  */
@@ -20,6 +20,9 @@ class TraitAccessTest extends UnitTestCase {
 
   use TestTrait;
 
+  /**
+   * Test if method acquired via the trait is found.
+   */
   public function testSimpleStuff() {
     $stuff = $this->getStuff();
     $this->assertSame($stuff, 'stuff', "Same old stuff");