bufio: fix UnreadByte
Also:
- fix error messages in tests
- make tests more symmetric
Fixes #7607.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/86180043
diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index 800c6d2..32ca861 100644
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -228,66 +228,94 @@
}
func TestUnreadRune(t *testing.T) {
- got := ""
segments := []string{"Hello, world:", "日本語"}
- data := strings.Join(segments, "")
r := NewReader(&StringReader{data: segments})
+ got := ""
+ want := strings.Join(segments, "")
// Normal execution.
for {
r1, _, err := r.ReadRune()
if err != nil {
if err != io.EOF {
- t.Error("unexpected EOF")
+ t.Error("unexpected error on ReadRune:", err)
}
break
}
got += string(r1)
- // Put it back and read it again
+ // Put it back and read it again.
if err = r.UnreadRune(); err != nil {
- t.Error("unexpected error on UnreadRune:", err)
+ t.Fatal("unexpected error on UnreadRune:", err)
}
r2, _, err := r.ReadRune()
if err != nil {
- t.Error("unexpected error reading after unreading:", err)
+ t.Fatal("unexpected error reading after unreading:", err)
}
if r1 != r2 {
- t.Errorf("incorrect rune after unread: got %c wanted %c", r1, r2)
+ t.Fatalf("incorrect rune after unread: got %c, want %c", r1, r2)
}
}
- if got != data {
- t.Errorf("want=%q got=%q", data, got)
+ if got != want {
+ t.Errorf("got %q, want %q", got, want)
}
}
func TestUnreadByte(t *testing.T) {
- want := "Hello, world"
- got := ""
segments := []string{"Hello, ", "world"}
r := NewReader(&StringReader{data: segments})
+ got := ""
+ want := strings.Join(segments, "")
// Normal execution.
for {
b1, err := r.ReadByte()
if err != nil {
if err != io.EOF {
- t.Fatal("unexpected EOF")
+ t.Error("unexpected error on ReadByte:", err)
}
break
}
got += string(b1)
- // Put it back and read it again
+ // Put it back and read it again.
if err = r.UnreadByte(); err != nil {
- t.Fatalf("unexpected error on UnreadByte: %v", err)
+ t.Fatal("unexpected error on UnreadByte:", err)
}
b2, err := r.ReadByte()
if err != nil {
- t.Fatalf("unexpected error reading after unreading: %v", err)
+ t.Fatal("unexpected error reading after unreading:", err)
}
if b1 != b2 {
- t.Fatalf("incorrect byte after unread: got %c wanted %c", b1, b2)
+ t.Fatalf("incorrect byte after unread: got %q, want %q", b1, b2)
}
}
if got != want {
- t.Errorf("got=%q want=%q", got, want)
+ t.Errorf("got %q, want %q", got, want)
+ }
+}
+
+func TestUnreadByteMultiple(t *testing.T) {
+ segments := []string{"Hello, ", "world"}
+ data := strings.Join(segments, "")
+ for n := 0; n <= len(data); n++ {
+ r := NewReader(&StringReader{data: segments})
+ // Read n bytes.
+ for i := 0; i < n; i++ {
+ b, err := r.ReadByte()
+ if err != nil {
+ t.Fatalf("n = %d: unexpected error on ReadByte: %v", n, err)
+ }
+ if b != data[i] {
+ t.Fatalf("n = %d: incorrect byte returned from ReadByte: got %q, want %q", n, b, data[i])
+ }
+ }
+ // Unread one byte if there is one.
+ if n > 0 {
+ if err := r.UnreadByte(); err != nil {
+ t.Errorf("n = %d: unexpected error on UnreadByte: %v", n, err)
+ }
+ }
+ // Test that we cannot unread any further.
+ if err := r.UnreadByte(); err == nil {
+ t.Errorf("n = %d: expected error on UnreadByte", n)
+ }
}
}
