protected function checkComposerConfig() {
    // @todo specify third key Acquia\\Blt\\Custom\\.
    $this->compareComposerConfig('autoload', 'psr-4');
    // @todo specify third key Drupal\\Tests\\PHPUnit\\\.
    $this->compareComposerConfig('autoload-dev', 'psr-4');
    $this->compareComposerConfig('extra', 'installer-paths');
    $this->compareComposerConfig('extra', 'enable-patching');
    $this->compareComposerConfig('extra', 'composer-exit-on-patch-failure');
    $this->compareComposerConfig('extra', 'patchLevel');
    $this->compareComposerConfig('repositories', 'drupal');
    $this->compareComposerConfig('scripts', 'nuke');
    $this->compareComposerConfig('scripts', 'drupal-scaffold');
  }