1 files changed, 86 insertions, 0 deletions
diff --git a/libgo/go/image/png/writer_test.go b/libgo/go/image/png/writer_test.go
new file mode 100644
index 0000000000..f218a5564b
--- /dev/null
+++ b/libgo/go/image/png/writer_test.go
@@ -0,0 +1,86 @@
+// Copyright 2009 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 png
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"io"
+	"os"
+	"testing"
+)
+
+func diff(m0, m1 image.Image) os.Error {
+	b0, b1 := m0.Bounds(), m1.Bounds()
+	if !b0.Eq(b1) {
+		return fmt.Errorf("dimensions differ: %v vs %v", b0, b1)
+	}
+	for y := b0.Min.Y; y < b0.Max.Y; y++ {
+		for x := b0.Min.X; x < b0.Max.X; x++ {
+			r0, g0, b0, a0 := m0.At(x, y).RGBA()
+			r1, g1, b1, a1 := m1.At(x, y).RGBA()
+			if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 {
+				return fmt.Errorf("colors differ at (%d, %d): %v vs %v", x, y, m0.At(x, y), m1.At(x, y))
+			}
+		}
+	}
+	return nil
+}
+
+func TestWriter(t *testing.T) {
+	// The filenames variable is declared in reader_test.go.
+	for _, fn := range filenames {
+		qfn := "testdata/pngsuite/" + fn + ".png"
+		// Read the image.
+		m0, err := readPng(qfn)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		// Read the image again, and push it through a pipe that encodes at the write end, and decodes at the read end.
+		pr, pw := io.Pipe()
+		defer pr.Close()
+		go func() {
+			defer pw.Close()
+			m1, err := readPng(qfn)
+			if err != nil {
+				t.Error(fn, err)
+				return
+			}
+			err = Encode(pw, m1)
+			if err != nil {
+				t.Error(fn, err)
+				return
+			}
+		}()
+		m2, err := Decode(pr)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		// Compare the two.
+		err = diff(m0, m2)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+	}
+}
+
+func BenchmarkEncodePaletted(b *testing.B) {
+	b.StopTimer()
+	img := image.NewPaletted(640, 480,
+		[]image.Color{
+			image.RGBAColor{0, 0, 0, 255},
+			image.RGBAColor{255, 255, 255, 255},
+		})
+	b.StartTimer()
+	buffer := new(bytes.Buffer)
+	for i := 0; i < b.N; i++ {
+		buffer.Reset()
+		Encode(buffer, img)
+	}
+}