From 45c8fbf0a2e71c0319784d003374af0a2495853f Mon Sep 17 00:00:00 2001
From: Fabian Bircher <f.bircher@gmail.com>
Date: Mon, 5 Oct 2020 23:20:44 +0200
Subject: [PATCH] Issue #3173393 by bircher: Add test traits to harmonize tests

---
 tests/src/Kernel/ConfigStorageTestTrait.php   | 146 ++++++++++++++++++
 tests/src/Kernel/ExampleStorageKernelTest.php |  81 ++++++++++
 2 files changed, 227 insertions(+)
 create mode 100644 tests/src/Kernel/ConfigStorageTestTrait.php
 create mode 100644 tests/src/Kernel/ExampleStorageKernelTest.php

diff --git a/tests/src/Kernel/ConfigStorageTestTrait.php b/tests/src/Kernel/ConfigStorageTestTrait.php
new file mode 100644
index 0000000..088681b
--- /dev/null
+++ b/tests/src/Kernel/ConfigStorageTestTrait.php
@@ -0,0 +1,146 @@
+<?php
+
+namespace Drupal\Tests\config_filter\Kernel;
+
+use Drupal\Core\Config\ExportStorageManager;
+use Drupal\Core\Config\FileStorage;
+use Drupal\Core\Config\ReadOnlyStorage;
+use Drupal\Core\Config\StorageInterface;
+use Drupal\Core\Lock\NullLockBackend;
+use Drupal\Core\Site\Settings;
+
+/**
+ * Trait to easily test import and export of config by comparing storages.
+ *
+ * The "new" config storage transformation API which was added to drupal 8.8
+ * transforms the storage before importing and exporting via the event system.
+ * This is a very different API from Config Filter 1.x but they work together.
+ *
+ * This test trait aims to provide methods to guide developers writing tests
+ * that work independently of whether the module uses Config Filter plugins or
+ * the new core events. You do this by comparing what you expect to be imported
+ * or exported.
+ *
+ * Drupal core <8.8 with config filter:
+ * export:
+ * [active] ----------------------------------------> [filter wrapping [sync]]
+ * import:
+ * [filter wrapping [sync]] ----------------------------------------> [active]
+ *
+ * Drupal core >=8.8:
+ * export:
+ * [active] ---------------> [export transformation] -----------------> [sync]
+ * import:
+ * [sync] -----------------> [import transformation] ---------------> [active]
+ *
+ * The test for exporting should set up the active store by saving config and
+ * what is expected to be exported and then compare the export storage with it.
+ * The test for importing should set up the sync store by writing files (or by
+ * saving arrays to the FileStorage) and then comparing the expectations with
+ * the import storage.
+ *
+ * Tests using this trait will work with Config Filter 1.x and 2.x and they will
+ * also work when using the core api directly provided the module has the same
+ * behaviour with the event listener as with the config filter plugin.
+ *
+ * @see \Drupal\Tests\config_filter\Kernel\ExampleStorageKernelTest
+ */
+trait ConfigStorageTestTrait {
+
+  /**
+   * Copies configuration objects from source storage to target storage.
+   *
+   * This method is defined in a trait used in KernelTestBase.
+   */
+  abstract protected function copyConfig(StorageInterface $source_storage, StorageInterface $target_storage);
+
+  /**
+   * The active config store, read only.
+   *
+   * @return \Drupal\Core\Config\StorageInterface
+   *   The storage with the active config.
+   */
+  protected function getActiveStorage(): StorageInterface {
+    // Return the active storage in read-only mode. Config should be properly
+    // saved and the active storage should not be directly manipulated.
+    return new ReadOnlyStorage($this->container->get('config.storage'));
+  }
+
+  /**
+   * The file storage associated with the sync storage.
+   *
+   * Use this to manipulate the files in the sync folder. In order to export the
+   * configuration to the sync storage use the following:
+   * @code
+   * $this->copyConfig($this->getExportStorage(), $this->getSyncFileStorage());
+   * @endcode
+   *
+   * @return \Drupal\Core\Config\StorageInterface
+   *   The storage with the files from the sync folder.
+   */
+  protected function getSyncFileStorage(): StorageInterface {
+    // We do not return the config.storage.sync service so that we can bypass
+    // config filter.
+    return new FileStorage(Settings::get('config_sync_directory'));
+  }
+
+  /**
+   * Trigger the export transformation and return its result.
+   *
+   * @return \Drupal\Core\Config\StorageInterface
+   *   The storage with the config to be exported.
+   */
+  protected function getExportStorage(): StorageInterface {
+    $manager = new ExportStorageManager(
+      $this->container->get('config.storage'),
+      $this->container->get('database'),
+      $this->container->get('event_dispatcher'),
+      // We use the null lock because these tests can anyway not be run in
+      // parallel. We would have to lock around accessing the storage and
+      // copying the content to a new memory storage.
+      new NullLockBackend()
+    );
+    // This is the same essentially as the config.storage.export service
+    // but the container doesn't cache it so we can access it several times
+    // with updated config in the same test and trigger the transformation anew.
+    return $manager->getStorage();
+  }
+
+  /**
+   * Trigger the import transformation and return its result.
+   *
+   * @return \Drupal\Core\Config\StorageInterface
+   *   The storage with the config to be imported.
+   */
+  protected function getImportStorage(): StorageInterface {
+    // Transform the sync storage for import.
+    return $this->container->get('config.import_transformer')->transform($this->container->get('config.storage.sync'));
+  }
+
+  /**
+   * Asserts that two config storage objects have the same content.
+   *
+   * @param \Drupal\Core\Config\StorageInterface $expected
+   *   The storage with the expected data.
+   * @param \Drupal\Core\Config\StorageInterface $actual
+   *   The storage with the actual data.
+   * @param string $message
+   *   The message to add to the assertion.
+   */
+  protected static function assertStorageEquals(StorageInterface $expected, StorageInterface $actual, string $message = '') {
+    // The same collections have to exist.
+    static::assertEqualsCanonicalizing($expected->getAllCollectionNames(), $actual->getAllCollectionNames(), $message);
+    // Now loop over all collections and assert the data to be equal.
+    foreach (array_merge([StorageInterface::DEFAULT_COLLECTION], $expected->getAllCollectionNames()) as $collection) {
+      $expected_collection = $expected->createCollection($collection);
+      $actual_collection = $actual->createCollection($collection);
+      // The same names are present in both.
+      static::assertEqualsCanonicalizing($expected_collection->listAll(), $actual_collection->listAll(), $message);
+      foreach ($expected_collection->listAll() as $name) {
+        // The same data can be read from both.
+        static::assertEquals($expected_collection->read($name), $actual_collection->read($name), $message . ' ' . $name);
+      }
+    }
+  }
+
+}
diff --git a/tests/src/Kernel/ExampleStorageKernelTest.php b/tests/src/Kernel/ExampleStorageKernelTest.php
new file mode 100644
index 0000000..bfa4ea5
--- /dev/null
+++ b/tests/src/Kernel/ExampleStorageKernelTest.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace Drupal\Tests\config_filter\Kernel;
+
+use Drupal\Core\Config\MemoryStorage;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Example class to test the export and import with the test trait.
+ *
+ * @group config_filter_example
+ */
+class ExampleStorageKernelTest extends KernelTestBase {
+
+  use ConfigStorageTestTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'system',
+    'config_filter',
+    'config_filter_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    // Install the system config.
+    $this->installConfig(['system']);
+
+    // Set the site name and slogan.
+    $this->config('system.site')->set('name', 'Config Test')->set('slogan', 'Testing is fun!')->save();
+  }
+
+  /**
+   * Example to test export.
+   */
+  public function testExampleExport() {
+    // Set up expectation for export.
+    $expectedExport = new MemoryStorage();
+    $this->copyConfig($this->getActiveStorage(), $expectedExport);
+
+    // Simulate the filter.
+    $system_site = $expectedExport->read('system.site');
+    // Exporting means triggering the write filter methods.
+    $system_site['slogan'] = 'Testing is fun! Arrr';
+    $expectedExport->write('system.site', $system_site);
+
+    // Do assertions.
+    static::assertStorageEquals($expectedExport, $this->getExportStorage());
+  }
+
+  /**
+   * Example to test import.
+   */
+  public function testExampleImport() {
+    // Write active config to file system as is.
+    // This is not a config export, but for the sake of the test we set up
+    // the sync storage to contain the same content as the active config.
+    $this->copyConfig($this->getActiveStorage(), $this->getSyncFileStorage());
+
+    // Set up expectation for import.
+    $expectedImport = new MemoryStorage();
+    $this->copyConfig($this->getSyncFileStorage(), $expectedImport);
+
+    // Simulate the filter.
+    $system_site = $expectedImport->read('system.site');
+    // Importing means triggering the read filter methods.
+    $system_site['name'] = 'Config Test Arrr';
+    $expectedImport->write('system.site', $system_site);
+
+    // Do assertions.
+    static::assertStorageEquals($expectedImport, $this->getImportStorage());
+  }
+
+}