class ConfigSnapshotTest

class ConfigSnapshotTest extends KernelTestBase {
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'config_test',
    'system',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->installConfig([
      'system',
    ]);
    // Update the config snapshot. This allows the parent::setUp() to write
    // configuration files.
    \Drupal::service('config.manager')->createSnapshot(\Drupal::service('config.storage'), \Drupal::service('config.storage.snapshot'));
    $this->copyConfig($this->container
      ->get('config.storage'), $this->container
      ->get('config.storage.sync'));
  }
  
  /**
   * Tests config snapshot creation and updating.
   */
  public function testSnapshot() {
    $active = $this->container
      ->get('config.storage');
    $sync = $this->container
      ->get('config.storage.sync');
    $snapshot = $this->container
      ->get('config.storage.snapshot');
    $config_name = 'config_test.system';
    $config_key = 'foo';
    $new_data = 'foobar';
    $active_snapshot_comparer = new StorageComparer($active, $snapshot);
    $sync_snapshot_comparer = new StorageComparer($sync, $snapshot);
    // Verify that we have an initial snapshot that matches the active
    // configuration. This has to be true as no config should be installed.
    $this->assertFalse($active_snapshot_comparer->createChangelist()
      ->hasChanges());
    // Install the default config.
    $this->installConfig([
      'config_test',
    ]);
    // Although we have imported config this has not affected the snapshot.
    $this->assertTrue($active_snapshot_comparer->reset()
      ->hasChanges());
    // Update the config snapshot.
    \Drupal::service('config.manager')->createSnapshot($active, $snapshot);
    // The snapshot and active config should now contain the same config
    // objects.
    $this->assertFalse($active_snapshot_comparer->reset()
      ->hasChanges());
    // Change a configuration value in sync.
    $sync_data = $this->config($config_name)
      ->get();
    $sync_data[$config_key] = $new_data;
    $sync->write($config_name, $sync_data);
    // Verify that active and snapshot match, and that sync doesn't match
    // active.
    $this->assertFalse($active_snapshot_comparer->reset()
      ->hasChanges());
    $this->assertTrue($sync_snapshot_comparer->createChangelist()
      ->hasChanges());
    // Import changed data from sync to active.
    $this->configImporter()
      ->import();
    // Verify changed config was properly imported.
    \Drupal::configFactory()->reset($config_name);
    $this->assertSame($new_data, $this->config($config_name)
      ->get($config_key));
    // Verify that a new snapshot was created which and that it matches
    // the active config.
    $this->assertFalse($active_snapshot_comparer->reset()
      ->hasChanges());
  }

}