code: @Test public void testRetrieveNextPairPatterns() throws Exception {
    String path="test/data/blackbox/rssexpanded-1/3.png";
    File file=new File(path);
    if (!file.exists()) {
      file=new File("core",path);
    }
    BufferedImage image=ImageIO.read(file);
    BinaryBitmap binaryMap=new BinaryBitmap(new GlobalHistogramBinarizer(new BufferedImageLuminanceSource(image)));
    int rowNumber=binaryMap.getHeight() / 2;
    BitArray row=binaryMap.getBlackRow(rowNumber,null);
    List<ExpandedPair> previousPairs=new ArrayList<ExpandedPair>();
    RSSExpandedReader rssExpandedReader=new RSSExpandedReader();
    ExpandedPair pair1=rssExpandedReader.retrieveNextPair(row,previousPairs,rowNumber);
    previousPairs.add(pair1);
    FinderPattern finderPattern=pair1.getFinderPattern();
    assertNotNull(finderPattern);
    assertEquals(0,finderPattern.getValue());
    ExpandedPair pair2=rssExpandedReader.retrieveNextPair(row,previousPairs,rowNumber);
    previousPairs.add(pair2);
    finderPattern=pair2.getFinderPattern();
    assertNotNull(finderPattern);
    assertEquals(0,finderPattern.getValue());
  }
  