Highlighting Lucene Wildcard Queries

Highlighting.cs

using System;
using Lucene.Net.Analysis.Snowball;
using Lucene.Net.Documents;
using Lucene.Net.Highlight;
using Lucene.Net.Index;
using Lucene.Net.Search;
using Lucene.Net.Store;
using NUnit.Framework;

namespace Lucene.Experiments.Tests
{
    [TestFixture]
    public class Highlighting
    {
        [Test]
        public void With_WildcardQuery()
        {
            const string text = "Here's text and something";
            const string fieldName = "z";
            var wildcardQuery = new WildcardQuery(new Term(fieldName, "some*"));
            Query query = wildcardQuery;
            var analyzer = new SnowballAnalyzer("English");
            var dir = new RAMDirectory();
            var writer = new IndexWriter(dir, analyzer, IndexWriter.MaxFieldLength.UNLIMITED);
            var doc = new Document();
            doc.Add(new Field(fieldName, text, Field.Store.NO, Field.Index.ANALYZED));
            writer.AddDocument(doc);
            writer.Flush(true, true, true);
            var reader = writer.GetReader();
            
            // Prove query for fun
            Console.WriteLine(query);
            var result = new IndexSearcher(reader).Search(query, null, 99);
            Assert.AreEqual(1, result.TotalHits);

            // The one in 2.9.4.1 that does the matching term lookus
            wildcardQuery.SetRewriteMethod(MultiTermQuery.SCORING_BOOLEAN_QUERY_REWRITE);
            
            query = wildcardQuery.Rewrite(reader);
            
            // Prove rewritten query with 'someth' from index
            Console.WriteLine(query);
            result = new IndexSearcher(reader).Search(query, null, 99);
            Assert.AreEqual(1, result.TotalHits);

            // And here's the magic
            var highlighter = new Highlighter(new SimpleHTMLFormatter("<span>", "</span>"), new QueryScorer(query, reader, fieldName));
            var bestFragment = highlighter.GetBestFragment(analyzer, fieldName, text);
            Assert.AreEqual("Here's text and <span>something</span>", bestFragment);
        }
    }
}