Property-based Junit test to check that zxing barcodes will round-trip with PURE_BARCODE

QRCodePureBarcodeRoundTripTest.java

package com.galois.qrstream.qrpipe;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Random;

import javax.imageio.ImageIO;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

import com.google.common.base.Charsets;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

/**
 * Property-based test to confirm that PURE_BARCODE can correctly decode any 
 * machine-generated qr codes.
 * 
 * @author creswick
 *
 */
@RunWith(Parameterized.class)
public class QRCodePureBarcodeRoundTripTest {

  private static final int COUNT = 30;

  @Parameters(name = "{0}")
  public static Collection<Object[]> setup() {
    List<Object[]> qrcodes = Lists.newArrayList();

    long seed = System.currentTimeMillis();
    Random rand = new Random(seed);
    for(int i = 0; i < COUNT; i++ ){
      byte[] bytes = new byte[1 + nextNatural(rand) % 768];
      rand.nextBytes(bytes);
      int height = 200;// + (nextNatural(rand) % 7) * 100;
      int width = 200;// + (nextNatural(rand) % 7) * 100;

      String data = new String(bytes, Charsets.ISO_8859_1);
      
      qrcodes.add(new Object[] { "seed: "+ seed + ": "+i
                               , data, height, width
      });
    }
    return qrcodes;
  }

  public static int nextNatural(Random r) {
    return Math.abs(r.nextInt());
  }

  private static BufferedImage encodeQRCode(String data, int height, int width)
      throws WriterException {
    QRCodeWriter writer = new QRCodeWriter();

    

    Map<EncodeHintType, Object> hints = Maps.newHashMap();
    hints.put(EncodeHintType.CHARACTER_SET, "ISO-8859-1");
    hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);

    BitMatrix bMat = writer.encode(data, BarcodeFormat.QR_CODE,
        width, height, hints);
    
    BufferedImage newCode = MatrixToImageWriter.toBufferedImage(bMat);
    return newCode;
  }

  private static Result decodeQRcode(BufferedImage image) throws NotFoundException,
      ChecksumException, FormatException {
    LuminanceSource source = new BufferedImageLuminanceSource(image);
    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

    Map<DecodeHintType, Object> hints = Maps.newHashMap();
    hints.put(DecodeHintType.CHARACTER_SET, "ISO-8859-1");
    hints.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE);

    // decode the barcode
    QRCodeReader reader = new QRCodeReader();
    Result res = reader.decode(bitmap, hints);
    //return getRawData(res);
    return res;
  }
  
  private String expected;
  private int height;
  private int width;
  
  public QRCodePureBarcodeRoundTripTest(String name, String data, int height, int width) {
    super();
    this.expected = data;
    this.height = height;
    this.width = width;
  }

  @Test
  public void test() throws WriterException, ChecksumException, FormatException, IOException {
    BufferedImage image = encodeQRCode(expected, height, width);
    Result res = null;
    try {
      res = decodeQRcode(image);
    } catch (NotFoundException e) {
      String dest = saveImage(image, "not-found-");
      fail("Could not locate QR Code in image: " + dest);
    }

    String actual = res.getText();
    if ( !actual.equals(expected) ) {
      String dest = saveImage(image, "failed-roundtrip-");
      assertEquals("Data did not roundtrip via image: " + dest,
          expected, actual);
    }
  }

  private String saveImage(BufferedImage image, String prefix) throws IOException {
    File outputFile =  File.createTempFile(prefix, ".png");
    ImageIO.write(image, "png", outputFile);

    return outputFile.getAbsolutePath();
  }
}