public void ToStrign_ShouldReturnCommaSeparatedListOfKeywords(List<string> keywords, MetaKeywordsModel model)
 {
   model.Keywords = keywords;
   var result = model.ToString();
   var keywordCollection = result.Split(new[] {','}, StringSplitOptions.RemoveEmptyEntries).ToList();
   var intersection = keywordCollection.Except(keywords);
   intersection.Count().Should().Be(0);
 }
    public static MetaKeywordsModel GetKeywords(Item item)
    {
      if (item.IsDerived(Templates.PageMetadata.ID))
      {
        var keywordsField = item.Fields[Templates.PageMetadata.Fields.Keywords];
        if (keywordsField == null)
        {
          return null;
        }

        var keywordMultilist = new MultilistField(keywordsField);
        var keywords = keywordMultilist.GetItems().Select(keywrdItem => keywrdItem[Templates.Keyword.Fields.Keyword]);
        var metaKeywordModel = new MetaKeywordsModel {Keywords = keywords.ToList()};

        return metaKeywordModel;
      }

      return null;
    }