function test_wp_get_attachment_image_srcset() {
    $_wp_additional_image_sizes = wp_get_additional_image_sizes();

    $image_meta = wp_get_attachment_metadata( self::$large_id );
    $size_array = array( 1600, 1200 ); // full size

    $srcset = wp_get_attachment_image_srcset( self::$large_id, $size_array, $image_meta );

    $year_month  = gmdate( 'Y/m' );
    $uploads_dir = 'http://' . WP_TESTS_DOMAIN . '/wp-content/uploads/';

    // Set up test cases for all expected size names.
    $intermediates = array( 'medium', 'medium_large', 'large', 'full' );

    foreach ( $_wp_additional_image_sizes as $name => $additional_size ) {
      if ( ! $_wp_additional_image_sizes[ $name ]['crop'] || 0 === $_wp_additional_image_sizes[ $name ]['height'] ) {
        $intermediates[] = $name;
      }
    }

    $expected = '';

    foreach ( $image_meta['sizes'] as $name => $size ) {
      // Whitelist the sizes that should be included so we pick up 'medium_large' in 4.4.
      if ( in_array( $name, $intermediates, true ) ) {
        $expected .= $uploads_dir . $year_month . '/' . $size['file'] . ' ' . $size['width'] . 'w, ';
      }
    }

    $expected .= $uploads_dir . $image_meta['file'] . ' ' . $image_meta['width'] . 'w';

    $expected_srcset = $this->_src_first( $expected, $uploads_dir . $image_meta['file'], $size_array[0] );

    $this->assertSame( $expected_srcset, $srcset );
  }