diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index 7a54d3cb26..a929226370 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -174,7 +174,8 @@ public function reset() {
     // We explicitly don't reset the addedFileNames as it is sort of a static
     // cache.
     // @todo In the long run it would be great to add the reset, but the early
-    //   installer fails due to that.
+    //   installer fails due to that. https://www.drupal.org/node/2719315 could
+    //   help to resolve with that.
     return $this;
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
index 3e4da510f6..da4b322a14 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
@@ -174,6 +174,34 @@ public function testGetPath() {
   }
 
   /**
+   * @covers ::reset
+   */
+  public function testReset() {
+    $test_extension_list = $this->setupTestExtensionList();
+
+    $path = $test_extension_list->getPath('test_name');
+    $this->assertEquals('vfs://drupal_root/example/test_name', $path);
+    $pathname = $test_extension_list->getPathname('test_name');
+    $this->assertEquals('vfs://drupal_root/example/test_name/test_name.info.yml', $pathname);
+    $filenames = $test_extension_list->getPathnames();
+    $this->assertEquals([
+      'test_name' => 'vfs://drupal_root/example/test_name/test_name.info.yml',
+    ], $filenames);
+
+    $test_extension_list->reset();
+
+    // Ensure that everything is still usable after the resetting.
+    $path = $test_extension_list->getPath('test_name');
+    $this->assertEquals('vfs://drupal_root/example/test_name', $path);
+    $pathname = $test_extension_list->getPathname('test_name');
+    $this->assertEquals('vfs://drupal_root/example/test_name/test_name.info.yml', $pathname);
+    $filenames = $test_extension_list->getPathnames();
+    $this->assertEquals([
+      'test_name' => 'vfs://drupal_root/example/test_name/test_name.info.yml',
+    ], $filenames);
+  }
+
+  /**
    * @return \Drupal\Tests\Core\Extension\TestExtension
    */
   protected function setupTestExtensionList($extension_names = ['test_name']) {