--- /dev/null
+// 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 image_test
+
+import (
+ "bufio"
+ "image"
+ "os"
+ "testing"
+
+ // TODO(nigeltao): implement bmp, gif and tiff decoders.
+ _ "image/jpeg"
+ _ "image/png"
+)
+
+const goldenFile = "testdata/video-001.png"
+
+type imageTest struct {
+ filename string
+ tolerance int
+}
+
+var imageTests = []imageTest{
+ //{"testdata/video-001.bmp", 0},
+ // GIF images are restricted to a 256-color palette and the conversion
+ // to GIF loses significant image quality.
+ //{"testdata/video-001.gif", 64<<8},
+ // JPEG is a lossy format and hence needs a non-zero tolerance.
+ {"testdata/video-001.jpeg", 8 << 8},
+ {"testdata/video-001.png", 0},
+ //{"testdata/video-001.tiff", 0},
+}
+
+func decode(filename string) (image.Image, string, os.Error) {
+ f, err := os.Open(filename, os.O_RDONLY, 0400)
+ if err != nil {
+ return nil, "", err
+ }
+ defer f.Close()
+ return image.Decode(bufio.NewReader(f))
+}
+
+func delta(u0, u1 uint32) int {
+ d := int(u0) - int(u1)
+ if d < 0 {
+ return -d
+ }
+ return d
+}
+
+func withinTolerance(c0, c1 image.Color, tolerance int) bool {
+ r0, g0, b0, a0 := c0.RGBA()
+ r1, g1, b1, a1 := c1.RGBA()
+ r := delta(r0, r1)
+ g := delta(g0, g1)
+ b := delta(b0, b1)
+ a := delta(a0, a1)
+ return r <= tolerance && g <= tolerance && b <= tolerance && a <= tolerance
+}
+
+func TestDecode(t *testing.T) {
+ golden, _, err := decode(goldenFile)
+ if err != nil {
+ t.Errorf("%s: %v", goldenFile, err)
+ }
+loop:
+ for _, it := range imageTests {
+ m, _, err := decode(it.filename)
+ if err != nil {
+ t.Errorf("%s: %v", it.filename, err)
+ continue loop
+ }
+ b := golden.Bounds()
+ if !b.Eq(m.Bounds()) {
+ t.Errorf("%s: want bounds %v got %v", it.filename, b, m.Bounds())
+ continue loop
+ }
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ for x := b.Min.X; x < b.Max.X; x++ {
+ if !withinTolerance(golden.At(x, y), m.At(x, y), it.tolerance) {
+ t.Errorf("%s: at (%d, %d), want %v got %v", it.filename, x, y, golden.At(x, y), m.At(x, y))
+ continue loop
+ }
+ }
+ }
+ }
+}
