tor-browser

test_imgtools.js (26803B)

---

/*
* Tests for imgITools
*/

const { NetUtil } = ChromeUtils.importESModule(
 "resource://gre/modules/NetUtil.sys.mjs"
);
const { AppConstants } = ChromeUtils.importESModule(
 "resource://gre/modules/AppConstants.sys.mjs"
);

/*
* dumpToFile()
*
* For test development, dumps the specified array to a file.
* Call |dumpToFile(outData);| in a test to file to a file.
*/
// eslint-disable-next-line no-unused-vars
function dumpToFile(aData) {
 var outputFile = do_get_cwd();
 outputFile.append("testdump.webp");

 var outputStream = Cc[
   "@mozilla.org/network/file-output-stream;1"
 ].createInstance(Ci.nsIFileOutputStream);
 // WR_ONLY|CREATE|TRUNC
 outputStream.init(outputFile, 0x02 | 0x08 | 0x20, 0o644, null);

 var bos = Cc["@mozilla.org/binaryoutputstream;1"].createInstance(
   Ci.nsIBinaryOutputStream
 );
 bos.setOutputStream(outputStream);

 bos.writeByteArray(aData);

 outputStream.close();
}

/*
* getFileInputStream()
*
* Returns an input stream for the specified file.
*/
function getFileInputStream(aFile) {
 var inputStream = Cc[
   "@mozilla.org/network/file-input-stream;1"
 ].createInstance(Ci.nsIFileInputStream);
 // init the stream as RD_ONLY, -1 == default permissions.
 inputStream.init(aFile, 0x01, -1, null);

 // Blah. The image decoders use ReadSegments, which isn't implemented on
 // file input streams. Use a buffered stream to make it work.
 var bis = Cc["@mozilla.org/network/buffered-input-stream;1"].createInstance(
   Ci.nsIBufferedInputStream
 );
 bis.init(inputStream, 1024);

 return bis;
}

/*
* streamToArray()
*
* Consumes an input stream, and returns its bytes as an array.
*/
function streamToArray(aStream) {
 var size = aStream.available();

 // use a binary input stream to grab the bytes.
 var bis = Cc["@mozilla.org/binaryinputstream;1"].createInstance(
   Ci.nsIBinaryInputStream
 );
 bis.setInputStream(aStream);

 var bytes = bis.readByteArray(size);
 if (size != bytes.length) {
   throw new Error("Didn't read expected number of bytes");
 }

 return bytes;
}

/*
* compareArrays
*
* Compares two arrays, and throws if there's a difference.
*/
function compareArrays(aArray1, aArray2) {
 Assert.equal(aArray1.length, aArray2.length);

 for (var i = 0; i < aArray1.length; i++) {
   if (aArray1[i] != aArray2[i]) {
     throw new Error("arrays differ at index " + i);
   }
 }
}

/*
* checkExpectedError
*
* Checks to see if a thrown error was expected or not, and if it
* matches the expected value.
*/
function checkExpectedError(aExpectedError, aActualError) {
 if (aExpectedError) {
   if (!aActualError) {
     throw new Error("Didn't throw as expected (" + aExpectedError + ")");
   }

   if (!aExpectedError.test(aActualError)) {
     throw new Error("Threw (" + aActualError + "), not (" + aExpectedError);
   }

   // We got the expected error, so make a note in the test log.
   dump("...that error was expected.\n\n");
 } else if (aActualError) {
   throw new Error("Threw unexpected error: " + aActualError);
 }
}

function run_test() {
 try {
   /* ========== 0 ========== */
   var testnum = 0;
   var testdesc = "imgITools setup";
   var err = null;

   var imgTools = Cc["@mozilla.org/image/tools;1"].getService(Ci.imgITools);

   if (!imgTools) {
     throw new Error("Couldn't get imgITools service");
   }

   // Ugh, this is an ugly hack. The pixel values we get in Windows are sometimes
   // +/- 1 value compared to other platforms, so we need to compare against a
   // different set of reference images. nsIXULRuntime.OS doesn't seem to be
   // available in xpcshell, so we'll use this as a kludgy way to figure out if
   // we're running on Windows.
   var isWindows = mozinfo.os == "win";

   /* ========== 1 ========== */
   testnum++;
   testdesc = "test decoding a PNG";

   // 64x64 png, 8415 bytes.
   var imgName = "image1.png";
   var inMimeType = "image/png";
   var imgFile = do_get_file(imgName);

   var istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 8415);

   var buffer = NetUtil.readInputStreamToString(istream, istream.available());
   var container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // It's not easy to look at the pixel values from JS, so just
   // check the container's size.
   Assert.equal(container.width, 64);
   Assert.equal(container.height, 64);

   /* ========== 2 ========== */
   testnum++;
   testdesc = "test encoding a scaled JPEG";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(container, "image/jpeg", 16, 16);

   var encodedBytes = streamToArray(istream);
   // Get bytes for expected result
   var refName = "image1png16x16.jpg";
   var refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1050);
   var referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 3 ========== */
   testnum++;
   testdesc = "test encoding an unscaled JPEG";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeImage(container, "image/jpeg");
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image1png64x64.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 4507);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 4 ========== */
   testnum++;
   testdesc = "test decoding a JPEG";

   // 32x32 jpeg, 3494 bytes.
   imgName = "image2.jpg";
   inMimeType = "image/jpeg";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 3494);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // It's not easy to look at the pixel values from JS, so just
   // check the container's size.
   Assert.equal(container.width, 32);
   Assert.equal(container.height, 32);

   /* ========== 5 ========== */
   testnum++;
   testdesc = "test encoding a scaled PNG";

   if (!isWindows) {
     // we'll reuse the container from the previous test
     istream = imgTools.encodeScaledImage(container, "image/png", 16, 16);

     encodedBytes = streamToArray(istream);
     // Get bytes for expected result
     if (AppConstants.USE_LIBZ_RS) {
       refName = "image2jpg16x16.libz-rs.png";
     } else {
       refName = isWindows ? "image2jpg16x16-win.png" : "image2jpg16x16.png";
     }
     refFile = do_get_file(refName);
     istream = getFileInputStream(refFile);
     Assert.equal(istream.available(), AppConstants.USE_LIBZ_RS ? 941 : 955);
     referenceBytes = streamToArray(istream);

     // compare the encoder's output to the reference file.
     compareArrays(encodedBytes, referenceBytes);
   }

   /* ========== 6 ========== */
   testnum++;
   testdesc = "test encoding an unscaled PNG";

   if (!isWindows) {
     // we'll reuse the container from the previous test
     istream = imgTools.encodeImage(container, "image/png");
     encodedBytes = streamToArray(istream);

     // Get bytes for expected result
     if (AppConstants.USE_LIBZ_RS) {
       refName = "image2jpg32x32.libz-rs.png";
     } else {
       refName = isWindows ? "image2jpg32x32-win.png" : "image2jpg32x32.png";
     }
     refFile = do_get_file(refName);
     istream = getFileInputStream(refFile);
     Assert.equal(istream.available(), AppConstants.USE_LIBZ_RS ? 2916 : 3026);
     referenceBytes = streamToArray(istream);

     // compare the encoder's output to the reference file.
     compareArrays(encodedBytes, referenceBytes);
   }

   /* ========== 7 ========== */
   testnum++;
   testdesc = "test decoding a ICO";

   // 16x16 ico, 1406 bytes.
   imgName = "image3.ico";
   inMimeType = "image/x-icon";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 1406);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // It's not easy to look at the pixel values from JS, so just
   // check the container's size.
   Assert.equal(container.width, 16);
   Assert.equal(container.height, 16);

   /* ========== 8 ========== */
   testnum++;
   testdesc = "test encoding a scaled PNG"; // note that we're scaling UP

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(container, "image/png", 32, 32);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = AppConstants.USE_LIBZ_RS
     ? "image3ico32x32.libz-rs.png"
     : "image3ico32x32.png";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), AppConstants.USE_LIBZ_RS ? 2285 : 2280);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 9 ========== */
   testnum++;
   testdesc = "test encoding an unscaled PNG";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeImage(container, "image/png");
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = AppConstants.USE_LIBZ_RS
     ? "image3ico16x16.libz-rs.png"
     : "image3ico16x16.png";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), AppConstants.USE_LIBZ_RS ? 512 : 520);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 10 ========== */
   testnum++;
   testdesc = "test decoding a GIF";

   // 32x32 gif, 1809 bytes.
   imgName = "image4.gif";
   inMimeType = "image/gif";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 1809);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // It's not easy to look at the pixel values from JS, so just
   // check the container's size.
   Assert.equal(container.width, 32);
   Assert.equal(container.height, 32);

   /* ========== 11 ========== */
   testnum++;
   testdesc =
     "test encoding an unscaled ICO with format options " +
     "(format=bmp;bpp=32)";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeImage(
     container,
     "image/vnd.microsoft.icon",
     "format=bmp;bpp=32"
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image4gif32x32bmp32bpp.ico";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 4286);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 12 ========== */
   testnum++;
   testdesc =
     // eslint-disable-next-line no-useless-concat
     "test encoding a scaled ICO with format options " + "(format=bmp;bpp=32)";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(
     container,
     "image/vnd.microsoft.icon",
     16,
     16,
     "format=bmp;bpp=32"
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image4gif16x16bmp32bpp.ico";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1150);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 13 ========== */
   testnum++;
   testdesc =
     "test encoding an unscaled ICO with format options " +
     "(format=bmp;bpp=24)";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeImage(
     container,
     "image/vnd.microsoft.icon",
     "format=bmp;bpp=24"
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image4gif32x32bmp24bpp.ico";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 3262);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 14 ========== */
   testnum++;
   testdesc =
     // eslint-disable-next-line no-useless-concat
     "test encoding a scaled ICO with format options " + "(format=bmp;bpp=24)";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(
     container,
     "image/vnd.microsoft.icon",
     16,
     16,
     "format=bmp;bpp=24"
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image4gif16x16bmp24bpp.ico";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 894);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 15 ========== */
   testnum++;
   testdesc = "test cropping a JPG";

   // 32x32 jpeg, 3494 bytes.
   imgName = "image2.jpg";
   inMimeType = "image/jpeg";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 3494);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // It's not easy to look at the pixel values from JS, so just
   // check the container's size.
   Assert.equal(container.width, 32);
   Assert.equal(container.height, 32);

   // encode a cropped image
   istream = imgTools.encodeCroppedImage(
     container,
     "image/jpeg",
     0,
     0,
     16,
     16
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg16x16cropped.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 879);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 16 ========== */
   testnum++;
   testdesc = "test cropping a JPG with an offset";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeCroppedImage(
     container,
     "image/jpeg",
     16,
     16,
     16,
     16
   );
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg16x16cropped2.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 878);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 17 ========== */
   testnum++;
   testdesc = "test cropping a JPG without a given height";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeCroppedImage(container, "image/jpeg", 0, 0, 16, 0);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg16x32cropped3.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1127);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 18 ========== */
   testnum++;
   testdesc = "test cropping a JPG without a given width";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeCroppedImage(container, "image/jpeg", 0, 0, 0, 16);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg32x16cropped4.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1135);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 19 ========== */
   testnum++;
   testdesc = "test cropping a JPG without a given width and height";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeCroppedImage(container, "image/jpeg", 0, 0, 0, 0);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg32x32.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1634);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 20 ========== */
   testnum++;
   testdesc = "test scaling a JPG without a given width";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(container, "image/jpeg", 0, 16);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg32x16scaled.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1227);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 21 ========== */
   testnum++;
   testdesc = "test scaling a JPG without a given height";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(container, "image/jpeg", 16, 0);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg16x32scaled.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1219);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 22 ========== */
   testnum++;
   testdesc = "test scaling a JPG without a given width and height";

   // we'll reuse the container from the previous test
   istream = imgTools.encodeScaledImage(container, "image/jpeg", 0, 0);
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image2jpg32x32.jpg";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1634);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 23 ========== */
   testnum++;
   testdesc = "test invalid arguments for cropping";

   var numErrors = 0;

   try {
     // width/height can't be negative
     imgTools.encodeScaledImage(container, "image/jpeg", -1, -1);
   } catch (e) {
     numErrors++;
   }

   try {
     // offsets can't be negative
     imgTools.encodeCroppedImage(container, "image/jpeg", -1, -1, 16, 16);
   } catch (e) {
     numErrors++;
   }

   try {
     // width/height can't be negative
     imgTools.encodeCroppedImage(container, "image/jpeg", 0, 0, -1, -1);
   } catch (e) {
     numErrors++;
   }

   try {
     // out of bounds
     imgTools.encodeCroppedImage(container, "image/jpeg", 17, 17, 16, 16);
   } catch (e) {
     numErrors++;
   }

   try {
     // out of bounds
     imgTools.encodeCroppedImage(container, "image/jpeg", 0, 0, 33, 33);
   } catch (e) {
     numErrors++;
   }

   try {
     // out of bounds
     imgTools.encodeCroppedImage(container, "image/jpeg", 1, 1, 0, 0);
   } catch (e) {
     numErrors++;
   }

   Assert.equal(numErrors, 6);

   /* ========== 24 ========== */
   testnum++;
   testdesc = "test encoding webp";

   // Load picture that we want to convert
   imgName = "image1.png";
   inMimeType = "image/png";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 8415);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // Convert image to webp
   istream = imgTools.encodeImage(container, "image/webp");
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image1.webp";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 3206);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== 25 ========== */
   testnum++;
   testdesc = "test encoding webp with quality parameter";

   // Load picture that we want to convert
   imgName = "image1.png";
   inMimeType = "image/png";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 8415);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   // Convert image to webp
   istream = imgTools.encodeImage(container, "image/webp", "quality=50");
   encodedBytes = streamToArray(istream);

   // Get bytes for expected result
   refName = "image1quality50.webp";
   refFile = do_get_file(refName);
   istream = getFileInputStream(refFile);
   Assert.equal(istream.available(), 1944);
   referenceBytes = streamToArray(istream);

   // compare the encoder's output to the reference file.
   compareArrays(encodedBytes, referenceBytes);

   /* ========== bug 363986 ========== */
   testnum = 363986;
   testdesc = "test PNG and JPEG and WEBP encoders' Read/ReadSegments methods";

   var testData = [
     {
       preImage: "image3.ico",
       preImageMimeType: "image/x-icon",
       refImage: AppConstants.USE_LIBZ_RS
         ? "image3ico16x16.libz-rs.png"
         : "image3ico16x16.png",
       refImageMimeType: "image/png",
     },
     {
       preImage: "image1.png",
       preImageMimeType: "image/png",
       refImage: "image1png64x64.jpg",
       refImageMimeType: "image/jpeg",
     },
     {
       preImage: "image1.png",
       preImageMimeType: "image/png",
       refImage: "image1.webp",
       refImageMimeType: "image/webp",
     },
   ];

   for (var i = 0; i < testData.length; ++i) {
     var dict = testData[i];

     imgFile = do_get_file(dict.refImage);
     istream = getFileInputStream(imgFile);
     var refBytes = streamToArray(istream);

     imgFile = do_get_file(dict.preImage);
     istream = getFileInputStream(imgFile);

     buffer = NetUtil.readInputStreamToString(istream, istream.available());
     container = imgTools.decodeImageFromBuffer(
       buffer,
       buffer.length,
       dict.preImageMimeType
     );

     istream = imgTools.encodeImage(container, dict.refImageMimeType);

     var sstream = Cc["@mozilla.org/storagestream;1"].createInstance(
       Ci.nsIStorageStream
     );
     sstream.init(4096, 4294967295, null);
     var ostream = sstream.getOutputStream(0);
     var bostream = Cc[
       "@mozilla.org/network/buffered-output-stream;1"
     ].createInstance(Ci.nsIBufferedOutputStream);

     // use a tiny buffer to make sure the image data doesn't fully fit in it
     bostream.init(ostream, 8);

     bostream.writeFrom(istream, istream.available());
     bostream.flush();
     bostream.close();

     var encBytes = streamToArray(sstream.newInputStream(0));

     compareArrays(refBytes, encBytes);
   }

   /* ========== bug 413512  ========== */
   testnum = 413512;
   testdesc = "test decoding bad favicon (bug 413512)";

   imgName = "bug413512.ico";
   inMimeType = "image/x-icon";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 17759);
   var errsrc = "none";

   try {
     buffer = NetUtil.readInputStreamToString(istream, istream.available());
     container = imgTools.decodeImageFromBuffer(
       buffer,
       buffer.length,
       inMimeType
     );

     // We expect to hit an error during encoding because the ICO header of the
     // image is fine, but the actual resources are corrupt. Since
     // decodeImageFromBuffer() only performs a metadata decode, it doesn't decode
     // far enough to realize this, but we'll find out when we do a full decode
     // during encodeImage().
     try {
       istream = imgTools.encodeImage(container, "image/png");
     } catch (e) {
       err = e;
       errsrc = "encode";
     }
   } catch (e) {
     err = e;
     errsrc = "decode";
   }

   Assert.equal(errsrc, "encode");
   checkExpectedError(/NS_ERROR_FAILURE/, err);

   /* ========== bug 815359  ========== */
   testnum = 815359;
   testdesc = "test correct ico hotspots (bug 815359)";

   imgName = "bug815359.ico";
   inMimeType = "image/x-icon";
   imgFile = do_get_file(imgName);

   istream = getFileInputStream(imgFile);
   Assert.equal(istream.available(), 4286);

   buffer = NetUtil.readInputStreamToString(istream, istream.available());
   container = imgTools.decodeImageFromBuffer(
     buffer,
     buffer.length,
     inMimeType
   );

   Assert.equal(container.hotspotX, 10);
   Assert.equal(container.hotspotY, 9);

   /* ========== end ========== */
 } catch (e) {
   throw new Error(
     "FAILED in test #" + testnum + " -- " + testdesc + ": " + e
   );
 }
}