code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2015 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.dev.bigdata;
  
  import org.junit.Ignore;
  import org.junit.Test;
  import org.languagetool.languagemodel.LuceneLanguageModel;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Arrays;
  
  import static org.junit.Assert.fail;
  
  public class LanguageModelSanityTest {
  
    private static final String NGRAM_DIR = "/data/google-ngram-index";
  
    @Test
    @Ignore("Interactive use only, requires local ngram index")
    public void testEnglishLanguageModelSanity() throws IOException {
      LuceneLanguageModel lm = new LuceneLanguageModel(new File(NGRAM_DIR));
      // 1gram:
      assertMatches(lm, "the");
      assertMatches(lm, "The");
      assertMatches(lm, ",");
      assertMatches(lm, "0");
      assertMatches(lm, "1");
      assertMatches(lm, "2");
      assertMatches(lm, "3");
      assertMatches(lm, "4");
      assertMatches(lm, "5");
      assertMatches(lm, "6");
      assertMatches(lm, "7");
      assertMatches(lm, "8");
      assertMatches(lm, "9");
      assertMatches(lm, ":");
      assertMatches(lm, "(");
      assertMatches(lm, ")");
      assertMatches(lm, "£");
      // 2gram:
      assertMatches(lm, "the man");
      assertMatches(lm, "The man");
      assertMatches(lm, "_START_ the");
      assertMatches(lm, "_START_ The");
      assertMatches(lm, "it _END_");
      assertMatches(lm, "it .");
      assertMatches(lm, "Also ,");
      assertMatches(lm, "is 0");
      assertMatches(lm, ": it");
      assertMatches(lm, "( it");
      assertMatches(lm, "it )");
      assertMatches(lm, "£ 5");
      // 3gram:
      assertMatches(lm, "the man who");
      assertMatches(lm, "The man who");
      assertMatches(lm, "_START_ The man");
      assertMatches(lm, "it was _END_");
      assertMatches(lm, "it was .");
      assertMatches(lm, "Also , it");
      assertMatches(lm, "it is 0");
      assertMatches(lm, ": it is");
      assertMatches(lm, "( it is");
      assertMatches(lm, "it is )");
      assertMatches(lm, "five - pound");
      assertMatches(lm, "is £ 5");
      assertMatches(lm, "it 's a");
      assertMatches(lm, "it ' s");
      // 4gram:
      assertMatches(lm, "the man who could");
      assertMatches(lm, "The man who could");
      assertMatches(lm, "five - pound note");
      assertMatches(lm, "_START_ The man who");
      assertMatches(lm, "which it was _END_");
      assertMatches(lm, "Also , it is");
      assertMatches(lm, "when it is 0");
      assertMatches(lm, "it is £ 5");
    }
  
    private void assertMatches(LuceneLanguageModel lm, String phrase) {
      String[] words = phrase.split(" ");
      long count = lm.getCount(Arrays.asList(words));
      System.out.println(Arrays.toString(words) + ": " +  count);
      if (count < 10) {
        fail("Only got " + count + " matches for " + Arrays.toString(words));
      }
    }
  
  }
  