InstallerExistingConfigTestBase is deprecated

The abstract class InstallerExistingConfigTestBase is now deprecated, use \Drupal\FunctionalTests\Installer\InstallerConfigDirectoryTestBase instead.

The method getConfigTarball has been replaced with the method getConfigLocation

The path should now point to a directory instead of a tarball.

Before:

class InstallerExistingConfigSyncDirectoryMultilingualTest extends InstallerExistingConfigTestBase

  protected function getConfigTarball() {
    return __DIR__ . '/../../../fixtures/config_install/multilingual.tar.gz';
  }

After

class InstallerExistingConfigSyncDirectoryMultilingualTest extends InstallerConfigDirectoryTestBase

  protected function getConfigLocation() {
    return __DIR__ . '/../../../fixtures/config_install/multilingual';
  }