diff --git a/plugin_type_example/src/Annotation/Sandwich.php b/plugin_type_example/src/Annotation/Sandwich.php
index 1b8f5a9..211fdf2 100644
--- a/plugin_type_example/src/Annotation/Sandwich.php
+++ b/plugin_type_example/src/Annotation/Sandwich.php
@@ -1,14 +1,5 @@
 <?php
 
-/**
- * @file
- * Contains \Drupal\plugin_type_example\Annotation\Sandwich.
- *
- * Provides an example of how to define a new annotation type for use in
- * defining a plugin type. Demonstrates documenting the various properties that
- * can be used in annotations for plugins of this type.
- */
-
 namespace Drupal\plugin_type_example\Annotation;
 
 use Drupal\Component\Annotation\Plugin;
@@ -16,12 +7,16 @@ use Drupal\Component\Annotation\Plugin;
 /**
  * Defines a Sandwich annotation object.
  *
- * @see \Drupal\plugin_type_example\SandwichPluginManager
- * @see plugin_api
+ * Provides an example of how to define a new annotation type for use in
+ * defining a plugin type. Demonstrates documenting the various properties that
+ * can be used in annotations for plugins of this type.
  *
  * Note that the "@ Annotation" line below is required and should be the last
  * line in the docblock. It's used for discovery of Annotation definitions.
  *
+ * @see \Drupal\plugin_type_example\SandwichPluginManager
+ * @see plugin_api
+ *
  * @Annotation
  */
 class Sandwich extends Plugin {
diff --git a/plugin_type_example/src/Controller/PluginTypeExampleController.php b/plugin_type_example/src/Controller/PluginTypeExampleController.php
index a22834d..90ca345 100644
--- a/plugin_type_example/src/Controller/PluginTypeExampleController.php
+++ b/plugin_type_example/src/Controller/PluginTypeExampleController.php
@@ -41,8 +41,8 @@ class PluginTypeExampleController extends ControllerBase {
    * \Drupal\plugin_type_example\Plugin\Sandwich namespace.
    *
    * @return array
-   *  Render API array with content for the page at
-   *  /examples/plugin_type_example.
+   *   Render API array with content for the page at
+   *   /examples/plugin_type_example.
    */
   public function description() {
     $build = array();
diff --git a/plugin_type_example/src/Plugin/Sandwich/ExampleMeatballSandwich.php b/plugin_type_example/src/Plugin/Sandwich/ExampleMeatballSandwich.php
index 10aa35f..12edcfa 100644
--- a/plugin_type_example/src/Plugin/Sandwich/ExampleMeatballSandwich.php
+++ b/plugin_type_example/src/Plugin/Sandwich/ExampleMeatballSandwich.php
@@ -31,6 +31,29 @@ use Drupal\plugin_type_example\SandwichBase;
 class ExampleMeatballSandwich extends SandwichBase {
 
   /**
+   * The day the sandwich is ordered.
+   *
+   * Since meatball sandwiches have a special behavior on Sundays, and since we
+   * want to test that behavior on days other than Sunday, we have to store the
+   * day as a property so we can test it.
+   *
+   * This is the string representation of the day of the week you get from
+   * date('D').
+   *
+   * @var string
+   */
+  protected $day;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
+    // Store the day so we can generate a special description on Sundays.
+    $this->day = date('D');
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+  }
+
+  /**
    * Place an order for a sandwich.
    *
    * This is just an example method on our plugin that we can call to get
@@ -49,12 +72,12 @@ class ExampleMeatballSandwich extends SandwichBase {
   }
 
   /**
-   * Override the parent class description method. We'll provide our own in this
-   * case.
+   * {@inheritdoc}
    */
   public function description() {
-    // On Sunday we only have day old bread.
-    if (date('D') == 'Sun') {
+    // We override the description() method in order to change the description
+    // text based on the date. On Sunday we only have day old bread.
+    if ($this->day == 'Sun') {
       return $this->t("Italian style meatballs drenched in irresistible marinara sauce, served on day old bread.");
     }
     return parent::description();
diff --git a/plugin_type_example/src/SandwichBase.php b/plugin_type_example/src/SandwichBase.php
index 4f28909..8a1cfc8 100644
--- a/plugin_type_example/src/SandwichBase.php
+++ b/plugin_type_example/src/SandwichBase.php
@@ -5,7 +5,7 @@ namespace Drupal\plugin_type_example;
 use Drupal\Component\Plugin\PluginBase;
 
 /**
- * Provides \Drupal\plugin_type_example\SandwichBase.
+ * A base class to help developers implement their own sandwich plugins.
  *
  * This is a helper class which makes it easier for other developers to
  * implement sandwich plugins in their own modules. In SandwichBase we provide
@@ -19,10 +19,10 @@ use Drupal\Component\Plugin\PluginBase;
  * needed to provide special handling around either of these things it could
  * just override the method in that class definition for that plugin.
  *
- * We intentionally declare our base class as abstract, and skip the order()
- * method required by \Drupal\plugin_type_example\SandwichInterface. This way
- * even if they are using our base class, developers will always be required to
- * define an order() method for their custom sandwich type.
+ * We intentionally declare our base class as abstract, and don't implement the
+ * order() method required by \Drupal\plugin_type_example\SandwichInterface.
+ * This way even if they are using our base class, developers will always be
+ * required to define an order() method for their custom sandwich type.
  *
  * @see \Drupal\plugin_type_example\Annotation\Sandwich
  * @see \Drupal\plugin_type_example\SandwichInterface
@@ -30,20 +30,18 @@ use Drupal\Component\Plugin\PluginBase;
 abstract class SandwichBase extends PluginBase implements SandwichInterface {
 
   /**
-   * Retrieve the @description property from the annotation and return it.
-   *
-   * @return string
+   * {@inheritdoc}
    */
   public function description() {
+    // Retrieve the @description property from the annotation and return it.
     return $this->pluginDefinition['description'];
   }
 
   /**
-   * Retrieve the @calories property from the annotation and return it.
-   *
-   * @return float
+   * {@inheritdoc}
    */
   public function calories() {
+    // Retrieve the @calories property from the annotation and return it.
     return (float) $this->pluginDefinition['calories'];
   }
 
diff --git a/plugin_type_example/src/SandwichInterface.php b/plugin_type_example/src/SandwichInterface.php
index 6d6b0af..98a32bf 100644
--- a/plugin_type_example/src/SandwichInterface.php
+++ b/plugin_type_example/src/SandwichInterface.php
@@ -47,4 +47,5 @@ interface SandwichInterface {
    *   Description of the sandwich that was just ordered.
    */
   public function order(array $extras);
+
 }
diff --git a/plugin_type_example/src/SandwichPluginManager.php b/plugin_type_example/src/SandwichPluginManager.php
index 9e68b9a..c6485c3 100644
--- a/plugin_type_example/src/SandwichPluginManager.php
+++ b/plugin_type_example/src/SandwichPluginManager.php
@@ -5,7 +5,6 @@ namespace Drupal\plugin_type_example;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Plugin\DefaultPluginManager;
-use Drupal\plugin_type_example\SandwichInterface;
 use Drupal\plugin_type_example\Annotation\Sandwich;
 
 /**
@@ -41,12 +40,13 @@ class SandwichPluginManager extends DefaultPluginManager {
     // This tells the plugin manager to look for Sandwich plugins in the
     // 'src/Plugin/Sandwich' subdirectory of any enabled modules. This also
     // serves to define the PSR-4 subnamespace in which sandwich plugins will
-    // live. Example: Drupal\{module_name}\Plugin\Sandwich\MySandwichPlugin;
+    // live. Modules can put a plugin class in their own namespace such as
+    // Drupal\{module_name}\Plugin\Sandwich\MySandwichPlugin.
     $subdir = 'Plugin/Sandwich';
 
     // The name of the interface that plugins should adhere to. Drupal will
     // enforce this as a requirement. If a plugin does not implement this
-    // interface, than Drupal will throw an error.
+    // interface, Drupal will throw an error.
     $plugin_interface = SandwichInterface::class;
 
     // The name of the annotation class that contains the plugin definition.
diff --git a/plugin_type_example/src/Tests/PluginTypeExampleTest.php b/plugin_type_example/src/Tests/PluginTypeExampleTest.php
index 90f75d2..6ac3eb8 100644
--- a/plugin_type_example/src/Tests/PluginTypeExampleTest.php
+++ b/plugin_type_example/src/Tests/PluginTypeExampleTest.php
@@ -3,6 +3,7 @@
 namespace Drupal\plugin_type_example\Tests;
 
 use Drupal\simpletest\WebTestBase;
+use Drupal\plugin_type_example\Plugin\Sandwich\ExampleHamSandwich;
 
 /**
  * Test the functionality of the Plugin Type Example module.
@@ -32,7 +33,8 @@ class PluginTypeExampleTest extends WebTestBase {
    * Test the plugin manager can be loaded, and the plugins are registered.
    */
   public function testPluginExample() {
-    $manager = \Drupal::service('plugin.manager.sandwich');
+    /* @var $manager \Drupal\plugin_type_example\SandwichPluginManager */
+    $manager = $this->container->get('plugin.manager.sandwich');
 
     $sandwich_plugin_definitions = $manager->getDefinitions();
 
@@ -49,7 +51,18 @@ class PluginTypeExampleTest extends WebTestBase {
     // Create an instance of the ham sandwich plugin to check it works.
     $plugin = $manager->createInstance('ham_sandwich', array('of' => 'configuration values'));
 
-    $this->assertEqual(get_class($plugin), 'Drupal\plugin_type_example\Plugin\Sandwich\ExampleHamSandwich', 'The ham sandwich plugin is instantiated and of the correct class.');
+    $this->assertEqual(get_class($plugin), ExampleHamSandwich::class, 'The ham sandwich plugin is instantiated and of the correct class.');
+
+    // Create a meatball sandwich so we can check it's special behavior on
+    // Sundays.
+    /* @var $meatball \Drupal\plugin_type_example\SandwichInterface */
+    $meatball = $manager->createInstance('meatball_sandwich');
+    // Set the $day property to 'Sun'.
+    $ref_day = new \ReflectionProperty($meatball, 'day');
+    $ref_day->setAccessible(TRUE);
+    $ref_day->setValue($meatball, 'Sun');
+    // Check the special description on Sunday.
+    $this->assertEqual($meatball->description(), 'Italian style meatballs drenched in irresistible marinara sauce, served on day old bread.');
   }
 
   /**