diff --git a/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginBagTest.php b/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginBagTest.php
index f49b106..4912808 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginBagTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Plugin/PluginBagTest.php
@@ -26,7 +26,7 @@ public static function getInfo() {
   }
 
   /**
-   * Tests the plugin bag.
+   * Tests the generic plugin bag.
    */
   protected function testPluginBag() {
     // Setup the plugin bag as well as the available plugin definitions.
@@ -38,7 +38,7 @@ protected function testPluginBag() {
       $this->assertTrue(isset($plugin_bag[$instance_id]), format_string('Plugin instance @instance_id exits on the bag', array('@instance_id' => $instance_id)));
     }
 
-    // A non existing instance_id shouldn't exists on the bag.
+    // A non existing instance_id shouldn't exist on the bag.
     $random_name = $this->randomName();
     $this->assertFalse(isset($plugin_bag[$random_name]), 'A random instance_id should not exist on the plugin bag.');
 
@@ -50,7 +50,7 @@ protected function testPluginBag() {
     unset($plugin_bag[$random_name]);
     $this->assertFalse(isset($plugin_bag[$random_name]), 'A random instance_id should not exist on the plugin bag after removing.');
 
-    // Check that iterating over the plugins work.
+    // Test that iterating over the plugins work.
     $expected_instance_ids = array_keys($definitions);
     $counter = 0;
     foreach ($plugin_bag as $instance_id => $plugin) {