https://api.drupal.org/api/drupal/core%21modules%21migrate_drupal_ui%21tests%21src%21Functional%21MigrateUpgradeTestBase.php/function/MigrateUpgradeTestBase%3A%3AloadFixture/11.x
function MigrateUpgradeTestBase::loadFixture | Drupal API
functiondrupalapi