t.Errorf("allocation occurred during write")
			}
			// Check that buffer has correct data.
			if !Equal(buf.Bytes()[0:startLen-readBytes], xBytes[readBytes:]) {
				t.Errorf("bad initial data at %d %d", startLen, growLen)
			}
			if !Equal(buf.Bytes()[startLen-readBytes:startLen-readBytes+growLen], yBytes) {
				t.Errorf("bad written data at %d %d", startLen, growLen)
			}
		}
	}
}

	if b.off > 0 {
		b.off--
	}
	return nil
}

// ReadBytes reads until the first occurrence of delim in the input,
// returning a slice containing the data up to and including the delimiter.
// If ReadBytes encounters an error before finding a delimiter,
// it returns the data read before the error and the error itself (often io.EOF).
// ReadBytes returns err != nil if and only if the returned data does not end in
// delim.

}

func TestReaderSimple(t *testing.T) {
	data := "hello world"
	b := NewReader(strings.NewReader(data))
	if s := readBytes(b); s != "hello world" {
		t.Errorf("simple hello world test failed: got %q", s)
	}

	b = NewReader(newRot13Reader(strings.NewReader(data)))
	if s := readBytes(b); s != "uryyb jbeyq" {
		t.Errorf("rot13 hello world test failed: got %q", s)
	}
}

type readMaker struct {
	name string

	totalLen += len(frag)
	return fullBuffers, frag, totalLen, err
}

// ReadBytes reads until the first occurrence of delim in the input,
// returning a slice containing the data up to and including the delimiter.
// If ReadBytes encounters an error before finding a delimiter,
// it returns the data read before the error and the error itself (often io.EOF).
// ReadBytes returns err != nil if and only if the returned data does not end in
// delim.

pkg bufio, method (*Reader) Peek(int) ([]uint8, error)
pkg bufio, method (*Reader) Read([]uint8) (int, error)
pkg bufio, method (*Reader) ReadByte() (uint8, error)
pkg bufio, method (*Reader) ReadBytes(uint8) ([]uint8, error)
pkg bufio, method (*Reader) ReadLine() ([]uint8, bool, error)
pkg bufio, method (*Reader) ReadRune() (int32, int, error)
pkg bufio, method (*Reader) ReadSlice(uint8) ([]uint8, error)