func testCodepage(t *testing.T, name string, inReader, outReader func(io.Reader) io.Reader) {
data := make([]byte, 256)
for i := range data {
data[i] = byte(i)
}
inr := inReader(bytes.NewBuffer(data))
r, err := charset.NewReader(name, inr)
if err != nil {
t.Fatalf("cannot make reader for charset %q: %v", name, err)
}
outr := outReader(r)
r = outr
var outbuf bytes.Buffer
w, err := charset.NewWriter(name, &outbuf)
if err != nil {
t.Fatalf("cannot make writer for charset %q: %v", name, err)
}
_, err = io.Copy(w, r)
if err != nil {
t.Fatalf("copy failed: %v", err)
}
err = w.Close()
if err != nil {
t.Fatalf("close failed: %v", err)
}
if len(outbuf.Bytes()) != len(data) {
t.Fatalf("short result of roundtrip, charset %q, readers %T, %T; expected 256, got %d", name, inr, outr, len(outbuf.Bytes()))
}
for i, x := range outbuf.Bytes() {
if data[i] != x {
t.Fatalf("charset %q, round trip expected %d, got %d", name, i, data[i])
}
}
}
func ExampleNewWriter() {
buf := new(bytes.Buffer)
w, err := charset.NewWriter("latin1", buf)
if err != nil {
log.Fatal(err)
}
fmt.Fprintf(w, "£5 for Peppé")
w.Close()
fmt.Printf("%q\n", buf.Bytes())
// Output: "\xa35 for Pepp\xe9"
}