public function test_validate_date_values_day_of_year() {
    // Valid values.
    $days_of_year = range( 1, 366 );
    foreach ( $days_of_year as $day_of_year ) {
      $this->assertTrue( $this->q->validate_date_values( array( 'dayofyear' => $day_of_year ) ) );
    }

    // Invalid values.
    $days_of_year = array( -1, 0, 367 );
    foreach ( $days_of_year as $day_of_year ) {
      $this->assertFalse( $this->q->validate_date_values( array( 'dayofyear' => $day_of_year ) ) );
    }
  }