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());
    }

}