protected function assertErrorResponse( $code, $response, $status = null ) {

    if ( is_a( $response, 'WP_REST_Response' ) ) {
      $response = $response->as_error();
    }

    $this->assertWPError( $response );
    $this->assertSame( $code, $response->get_error_code() );

    if ( null !== $status ) {
      $data = $response->get_error_data();
      $this->assertArrayHasKey( 'status', $data );
      $this->assertSame( $status, $data['status'] );
    }
  }