Issue #3260846 by Luke.Leber: Update hook missing in HEAD for new option defaults

inline_all_css.post_update.php

+<?php
+
+/**
+ * @file
+ * Contains post update functions for Inline All CSS.
+ */
+
+/**
+ * Ensure that module behavior does not change from the RC2 release.
+ */
+function inline_all_css_post_update_retain_rc2_state() {
+  \Drupal::configFactory()
+    ->getEditable('inline_all_css.settings')
+    ->set('enabled', TRUE)
+    ->save();
+}

tests/fixtures/update/inline_all_css.update-hook-test.php

+<?php
+
+/**
+ * @file
+ * Sets up the database state for the upgrade path tests.
+ */
+
+use Drupal\Core\Database\Database;
+
+$connection = Database::getConnection();
+
+// Set the schema version.
+$connection->merge('key_value')
+  ->condition('collection', 'system.schema')
+  ->condition('name', 'inline_all_css')
+  ->fields([
+    'collection' => 'system.schema',
+    'name' => 'inline_all_css',
+    'value' => 's:4:"9000";',
+  ])
+  ->execute();
+
+// Add the proper core.extension configuration.
+$extensions = $connection->select('config')
+  ->fields('config', ['data'])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute()
+  ->fetchField();
+$extensions = unserialize($extensions, ['allowed_classes' => []]);
+$extensions['module']['inline_all_css'] = 9000;
+$connection->update('config')
+  ->fields([
+    'data' => serialize($extensions),
+  ])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute();

tests/src/Functional/PostUpdateTest.php

+<?php
+
+namespace Drupal\Tests\inline_all_css\Functional;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+
+/**
+ * Test cases for the incremental upgrade path.
+ *
+ * @group inline_all_css
+ */
+class PostUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * The config factory service.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $configFactory;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->configFactory = $this->container->get('config.factory');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      DRUPAL_ROOT . '/core/modules/system/tests/fixtures/update/drupal-9.0.0.bare.standard.php.gz',
+      __DIR__ . '/../../fixtures/update/inline_all_css.update-hook-test.php',
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function doSelectionTest() {
+    parent::doSelectionTest();
+    $this->assertSession()->responseContains('Ensure that module behavior does not change from the RC2 release.');
+  }
+
+  /**
+   * Test case for the upgrade path.
+   */
+  public function testUpgrade() {
+    static::assertArrayNotHasKey('inline_all_css.settings', $this->configFactory->listAll());
+    $this->runUpdates();
+    static::assertTrue($this->config('inline_all_css.settings')->get('enabled'));
+  }
+
+}

tests/src/Kernel/CssCollectionRendererTest.php

@@ -173,9 +173,6 @@ CSS
 
   /**
    * Sets up the CSS to add in the dispatched event.
-   *
-   * @param string $css
-   *   The CSS to add.
    */
   protected function setEventCss() {
     $this->eventDispatcher->method('dispatch')