trait IntrospectionTestTrait in GraphQL 8.3

trait IntrospectionTestTrait {

  /**
   * Retrieve a name-index schema to easy assert type system plugins.
   *
   * @return array
   *   The name-indexed schema.
   */
  protected function introspect() {
    if (method_exists($this, 'resetStaticCaches')) {
      $this
        ->resetStaticCaches();
    }
    $introspection = $this->container
      ->get('graphql.introspection')
      ->introspect($this
      ->getDefaultSchema());
    $this
      ->indexByName($introspection['data']);
    return $introspection['data']['__schema'];
  }

  /**
   * Assert certain fields in the GraphQL schema.
   *
   * @param array $fields
   *   Array of [ParentType, FieldName, FieldType] triples. Field type can use
   *   the GraphQL type notation.
   * @param bool $invert
   *   Invert the result and check for non-existence instead.
   */
  protected function assertGraphQLFields(array $fields, $invert = FALSE) {
    $schema = $this
      ->introspect();
    foreach ($fields as list($parent, $name, $type)) {
      $this
        ->assertArrayHasKey($parent, $schema['types'], "Type {$parent} not found.");
      if ($invert) {
        $this
          ->assertArrayNotHasKey($name, $schema['types'][$parent]['fields'], "Field {$name} found on type {$parent}.");
        continue;
      }
      $this
        ->assertArrayHasKey($parent, $schema['types'], "Type {$parent} not found.");
      $this
        ->assertArrayHasKey($name, $schema['types'][$parent]['fields'], "Field {$name} not found on type {$parent}.");
      $field = $schema['types'][$parent]['fields'][$name];
      list($type, $decorators) = StringHelper::parseType($type);
      $decorators = array_map(function ($decorator) {
        return $decorator[1];
      }, $decorators);
      if (in_array('listOf', $decorators)) {
        $this
          ->assertEquals('LIST', $field['type']['kind'], "Expected field {$name} to be a list.");
        $this
          ->assertEquals($type, $field['type']['ofType']['name'], "Expected field {$name} to be a list of {$type}.");
      }
      else {
        $this
          ->assertEquals($type, $field['type']['name'], "Expected field {$name} to be {$type}.");
      }
    }
  }

  /**
   * Recursively index all sequences by name.
   *
   * @param array $data
   *   The input array.
   *
   * @internal
   */
  private function indexByName(array &$data) {
    if (count(array_filter(array_keys($data), 'is_int')) == count($data)) {

      // This is a list, remap it.
      $data = array_combine(array_map(function ($key, $row) {
        return is_array($row) && isset($row['name']) ? $row['name'] : $key;
      }, array_keys($data), $data), $data);
    }
    foreach (array_keys($data) as $key) {
      if (is_array($data[$key])) {
        $this
          ->indexByName($data[$key]);
      }
    }
  }

}