Issue #2678770 by alexpott, tstoeckler, Gábor Hojtsy: Random fail with third party shortcut settings schema on seven theme

core/modules/shortcut/shortcut.install

@@ -64,6 +64,6 @@ function shortcut_uninstall() {
   // Theme settings are not configuration entities and cannot depend on modules
   // so to unset a module-specific setting, we need to unset it with logic.
   if (\Drupal::service('theme_handler')->themeExists('seven')) {
-    \Drupal::configFactory()->getEditable('seven.settings')->clear('third_party_settings.shortcut.module_link')->save(TRUE);
+    \Drupal::configFactory()->getEditable('seven.settings')->clear('third_party_settings.shortcut')->save(TRUE);
   }
 }

core/modules/shortcut/tests/src/Kernel/ShortcutSevenIntegrationTest.php

@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\shortcut\Kernel\ShortcutSevenIntegrationTest.
+ */
+
+namespace Drupal\Tests\shortcut\Kernel;
+
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests shortcut_install() and shortcut_uninstall().
+ *
+ * @group shortcut
+ */
+class ShortcutSevenIntegrationTest extends KernelTestBase {
+
+  public static $modules = ['system'];
+
+  /**
+   * Tests shortcut_install() and shortcut_uninstall().
+   */
+  public function testInstallUninstall() {
+    // Install seven.
+    \Drupal::service('theme_installer')->install(['seven']);
+    $this->assertNull($this->config('seven.settings')->get('third_party_settings.shortcut'), 'There are no shortcut settings in seven.settings.');
+
+    \Drupal::service('module_installer')->install(['shortcut']);
+    $this->assertTrue($this->config('seven.settings')->get('third_party_settings.shortcut.module_link'), 'The shortcut module_link setting is in seven.settings.');
+
+    \Drupal::service('module_installer')->uninstall(['shortcut']);
+    $this->assertNull($this->config('seven.settings')->get('third_party_settings.shortcut'), 'There are no shortcut settings in seven.settings.');
+  }
+
+}