code review 105750045: go.image/tiff: fix (TIFF-specific) LZW decompression.

tiff/reader_test.go

 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package tiff
 
 import (
         "image"
         "io/ioutil"
         "os"
@@ skipping 107 matching lines @@
         if err != nil {
                 t.Fatal(err)
         }
 
         compare(t, img0, img1)
         compare(t, img0, img2)
         compare(t, img0, img3)
         compare(t, img0, img4)
 }
 
+// TestDecodeLZW tests that decoding a PNG image and a LZW-compressed TIFF image
+// result in the same pixel data.
+func TestDecodeLZW(t *testing.T) {
+        img0, err := load("blue-purple-pink.png")
+        if err != nil {
+                t.Fatal(err)
+        }
+        img1, err := load("blue-purple-pink.lzwcompressed.tiff")
+        if err != nil {
+                t.Fatal(err)
+        }
+
+        compare(t, img0, img1)
+}
+
 // TestDecompress tests that decoding some TIFF images that use different
 // compression formats result in the same pixel data.
 func TestDecompress(t *testing.T) {
         var decompressTests = []string{
                 "bw-uncompressed.tiff",
                 "bw-deflate.tiff",
                 "bw-packbits.tiff",
         }
         var img0 image.Image
         for _, name := range decompressTests {
@@ skipping 21 matching lines @@
         for i := 0; i < b.N; i++ {
                 _, err := Decode(r)
                 if err != nil {
                         b.Fatal("Decode:", err)
                 }
         }
 }
 
 func BenchmarkDecodeCompressed(b *testing.B)   { benchmarkDecode(b, "video-001.tiff") }
 func BenchmarkDecodeUncompressed(b *testing.B) { benchmarkDecode(b, "video-001-uncompressed.tiff") }