clearStaticCache example

->set('label', 'Original')
      ->save();
    \Drupal::languageManager()
      ->getLanguageConfigOverride('de', 'config_test.foo')
      ->set('value', ['key' => 'override'])
      ->set('label', 'Override')
      ->save();
    \Drupal::languageManager()
      ->getLanguageConfigOverride('fr', 'config_test.foo')
      ->set('value', ['key' => 'override'])
      ->save();
    \Drupal::configFactory()->clearStaticCache();
    $config = \Drupal::config('config_test.foo');
    $this->assertSame(['key' => 'override'], $config->get('value'));

    // Ensure renaming the config will rename the override.     \Drupal::languageManager()->setConfigOverrideLanguage(\Drupal::languageManager()->getLanguage('en'));
    \Drupal::configFactory()->rename('config_test.foo', 'config_test.bar');
    $config = \Drupal::config('config_test.bar');
    $this->assertEquals(['key' => 'original'], $config->get('value'));
    $override = \Drupal::languageManager()->getLanguageConfigOverride('de', 'config_test.foo');
    $this->assertTrue($override->isNew());
    $this->assertNull($override->get('value'));