$type_registry->register_interface_type('MyTestNodeInterface', [
    'fields' => [
        'id' => [
            'type' => ['non_null' => 'ID'],
            'resolve' => function ($source, $args, $context, $info) {
                // check correct format
                return 'correctFormat==';
            },
        ],
        'databaseId' => [
            'type' => 'ID',
            'resolve' => function ($source, $args, $context, $info) {
                return 'interface_db_id==';
            },
        ],
    ]
]);

$type_registry->register_object_type('MyTestObject', [
    'interfaces' => ['MyTestNodeInterface'],
    'fields' => [
        'id' => [
            'type' => ['non_null' => 'ID'],
            'resolve' => function ($source, $args, $context, $info) {
                return 'not_correct_format==';
            },
        ],
        'hello' => [
            'type' => 'String',
            'resolve' => function ($source, $args, $context, $info) {
                return 'hello from object';
            },
        ],
    ],
]);

$type_registry->register_field('RootQuery', 'myTestQuery', [
    'type' => 'MyTestObject',
    'description' => 'A field that returns a MyTestObject',
    'resolve' => function ($source, $args, $context, $info) {
        return [];
    },
]);