adding a testcase for FuzzyQuery

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git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@150378 13f79535-47bb-0310-9956-ffa450edef68

src/test/org/apache/lucene/search/TestFuzzyQuery.java

@@ -0,0 +1,137 @@
+package org.apache.lucene.search;
+
+/**
+ * Copyright 2004 The Apache Software Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.IOException;
+
+import junit.framework.TestCase;
+import org.apache.lucene.analysis.WhitespaceAnalyzer;
+import org.apache.lucene.document.Document;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.Term;
+import org.apache.lucene.store.RAMDirectory;
+
+/**
+ * Tests {@link FuzzyQuery}.
+ *
+ * @author Daniel Naber
+ */
+public class TestFuzzyQuery extends TestCase {
+
+  public void testDefaultFuzziness() throws Exception {
+    RAMDirectory directory = new RAMDirectory();
+    IndexWriter writer = new IndexWriter(directory, new WhitespaceAnalyzer(), true);
+    addDoc("aaaaa", writer);
+    addDoc("aaaab", writer);
+    addDoc("aaabb", writer);
+    addDoc("aabbb", writer);
+    addDoc("abbbb", writer);
+    addDoc("bbbbb", writer);
+    addDoc("ddddd", writer);
+    writer.optimize();
+    writer.close();
+    IndexSearcher searcher = new IndexSearcher(directory);
+
+    FuzzyQuery query = new FuzzyQuery(new Term("field", "aaaaa"));   
+    Hits hits = searcher.search(query);
+    assertEquals(3, hits.length());
+
+    // not similar enough:
+    query = new FuzzyQuery(new Term("field", "xxxxx"));  	
+    hits = searcher.search(query);
+    assertEquals(0, hits.length());
+    query = new FuzzyQuery(new Term("field", "aaccc"));   // edit distance to "aaaaa" = 3
+    hits = searcher.search(query);
+    assertEquals(0, hits.length());
+
+    // query identical to a word in the index:
+    query = new FuzzyQuery(new Term("field", "aaaaa"));   
+    hits = searcher.search(query);
+    assertEquals(3, hits.length());
+    assertEquals(hits.doc(0).get("field"), ("aaaaa"));
+    // default allows for up to two edits:
+    assertEquals(hits.doc(1).get("field"), ("aaaab"));
+    assertEquals(hits.doc(2).get("field"), ("aaabb"));
+
+    // query similar to a word in the index:
+    query = new FuzzyQuery(new Term("field", "aaaac"));   
+    hits = searcher.search(query);
+    assertEquals(3, hits.length());
+    assertEquals(hits.doc(0).get("field"), ("aaaaa"));
+    assertEquals(hits.doc(1).get("field"), ("aaaab"));
+    assertEquals(hits.doc(2).get("field"), ("aaabb"));
+
+    query = new FuzzyQuery(new Term("field", "ddddX"));   
+    hits = searcher.search(query);
+    assertEquals(1, hits.length());
+    assertEquals(hits.doc(0).get("field"), ("ddddd"));
+
+    // different field = no match:
+    query = new FuzzyQuery(new Term("anotherfield", "ddddX"));   
+    hits = searcher.search(query);
+    assertEquals(0, hits.length());
+
+    searcher.close();
+    directory.close();
+  }
+
+  public void testDefaultFuzzinessLong() throws Exception {
+    RAMDirectory directory = new RAMDirectory();
+    IndexWriter writer = new IndexWriter(directory, new WhitespaceAnalyzer(), true);
+    addDoc("aaaaaaa", writer);
+    addDoc("segment", writer);
+    writer.optimize();
+    writer.close();
+    IndexSearcher searcher = new IndexSearcher(directory);
+
+    FuzzyQuery query;
+    // not similar enough:
+    query = new FuzzyQuery(new Term("field", "xxxxx"));   
+    Hits hits = searcher.search(query);
+    assertEquals(0, hits.length());
+    // edit distance to "aaaaaaa" = 3, this matches because the string is longer than
+    // in testDefaultFuzziness so a bigger difference is allowed:
+    query = new FuzzyQuery(new Term("field", "aaaaccc"));   
+    hits = searcher.search(query);
+    assertEquals(1, hits.length());
+    assertEquals(hits.doc(0).get("field"), ("aaaaaaa"));
+
+    // no match, more than half of the characters is wrong:
+    query = new FuzzyQuery(new Term("field", "aaacccc"));   
+    hits = searcher.search(query);
+    assertEquals(0, hits.length());
+
+    // "student" and "stellent" are indeed similar to "segment" by default:
+    query = new FuzzyQuery(new Term("field", "student"));   
+    hits = searcher.search(query);
+    assertEquals(1, hits.length());
+    query = new FuzzyQuery(new Term("field", "stellent"));   
+    hits = searcher.search(query);
+    assertEquals(1, hits.length());
+
+    searcher.close();
+    directory.close();
+  }
+  
+  private void addDoc(String text, IndexWriter writer) throws IOException {
+    Document doc = new Document();
+    doc.add(Field.Text("field", text));
+    writer.addDocument(doc);
+  }
+
+}