bufio: add UnreadRune.
R=rsc
CC=golang-dev
https://golang.org/cl/2103046
diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index 876270f..10c14ec 100644
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -226,6 +226,99 @@
}
}
+func TestUnreadRune(t *testing.T) {
+ got := ""
+ segments := []string{"Hello, world:", "日本語"}
+ data := strings.Join(segments, "")
+ r := NewReader(&StringReader{data: segments})
+ // Normal execution.
+ for {
+ rune, _, err := r.ReadRune()
+ if err != nil {
+ if err != os.EOF {
+ t.Error("unexpected EOF")
+ }
+ break
+ }
+ got += string(rune)
+ // Put it back and read it again
+ if err = r.UnreadRune(); err != nil {
+ t.Error("unexpected error on UnreadRune:", err)
+ }
+ rune1, _, err := r.ReadRune()
+ if err != nil {
+ t.Error("unexpected error reading after unreading:", err)
+ }
+ if rune != rune1 {
+ t.Error("incorrect rune after unread: got %c wanted %c", rune1, rune)
+ }
+ }
+ if got != data {
+ t.Errorf("want=%q got=%q", data, got)
+ }
+}
+
+// Test that UnreadRune fails if the preceding operation was not a ReadRune.
+func TestUnreadRuneError(t *testing.T) {
+ buf := make([]byte, 3) // All runes in this test are 3 bytes long
+ r := NewReader(&StringReader{data: []string{"日本語日本語日本語"}})
+ if r.UnreadRune() == nil {
+ t.Error("expected error on UnreadRune from fresh buffer")
+ }
+ _, _, err := r.ReadRune()
+ if err != nil {
+ t.Error("unexpected error on ReadRune (1):", err)
+ }
+ if err = r.UnreadRune(); err != nil {
+ t.Error("unexpected error on UnreadRune (1):", err)
+ }
+ if r.UnreadRune() == nil {
+ t.Error("expected error after UnreadRune (1)")
+ }
+ // Test error after Read.
+ _, _, err = r.ReadRune() // reset state
+ if err != nil {
+ t.Error("unexpected error on ReadRune (2):", err)
+ }
+ _, err = r.Read(buf)
+ if err != nil {
+ t.Error("unexpected error on Read (2):", err)
+ }
+ if r.UnreadRune() == nil {
+ t.Error("expected error after Read (2)")
+ }
+ // Test error after ReadByte.
+ _, _, err = r.ReadRune() // reset state
+ if err != nil {
+ t.Error("unexpected error on ReadRune (2):", err)
+ }
+ for _ = range buf {
+ _, err = r.ReadByte()
+ if err != nil {
+ t.Error("unexpected error on ReadByte (2):", err)
+ }
+ }
+ if r.UnreadRune() == nil {
+ t.Error("expected error after ReadByte")
+ }
+ // Test error after UnreadByte.
+ _, _, err = r.ReadRune() // reset state
+ if err != nil {
+ t.Error("unexpected error on ReadRune (3):", err)
+ }
+ _, err = r.ReadByte()
+ if err != nil {
+ t.Error("unexpected error on ReadByte (3):", err)
+ }
+ err = r.UnreadByte()
+ if err != nil {
+ t.Error("unexpected error on UnreadByte (3):", err)
+ }
+ if r.UnreadRune() == nil {
+ t.Error("expected error after UnreadByte (3)")
+ }
+}
+
func TestReadWriteRune(t *testing.T) {
const NRune = 1000
byteBuf := new(bytes.Buffer)
