code: /* LanguageTool, a natural language style checker
   * Copyright (C) 2021 Daniel Naber (http://www.danielnaber.de)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
   * USA
   */
  package org.languagetool.server;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import org.junit.Ignore;
  import org.junit.Test;
  
  import java.io.IOException;
  import java.net.URL;
  import java.net.URLEncoder;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Simple interactive test to see how much of a string can be removed before language
   * identification starts to fail. Requires server to be manually started locally.
   */
  public class LanguageIdentificationTest {
  
    @Test
    @Ignore("for interactive use, to find cases where e.g. ngram-based language detection makes a difference")
    public void testEverShorterText() throws IOException {
      String expected = "de-DE";
      List<String> lines = Files.readAllLines(Paths.get("/home/dnaber/lt/lang-detect-test.txt"));
      ObjectMapper mapper = new ObjectMapper();
      System.out.println("Loaded " + lines.size() + " lines");
      int lineCount = 0;
      for (String line : lines) {
        //System.out.println(line);
        lineCount++;
        for (int i = line.length(); i > 0; i--) {
          String shortened = line.substring(0, i);
          String json = check(shortened);
          Map map = mapper.readValue(json, Map.class);
          Map languageObj = (Map<String, String>) map.get("language");
          Map<String, String> detectedLanguageObj = (Map<String, String>) languageObj.get("detectedLanguage");
          if (!detectedLanguageObj.get("code").equals(expected)) {
            System.out.println(lineCount + ". " + detectedLanguageObj.get("code") + " " + shortened + " @" + shortened.length());
            break;
          }
        }
      }
    }
  
    private String check(String text) throws IOException {
      String urlOptions = "/v2/check?language=auto";
      urlOptions += "&text=" + URLEncoder.encode(text, "UTF-8");
      URL url = new URL("http://localhost:" + HTTPTestTools.getDefaultPort() + urlOptions);
      return HTTPTestTools.checkAtUrl(url);
    }
  
  }
  