t.Fatalf("ReadRune(%U) after UnreadRune got %U,%d not %U,%d (err=%s)", r, r2, nbytes, r, size, err)
		}
	}
}

func TestWriteInvalidRune(t *testing.T) {
	// Invalid runes, including negative ones, should be written as
	// utf8.RuneError.
	for _, r := range []rune{-1, utf8.MaxRune + 1} {
		var buf Buffer
		buf.WriteRune(r)

</li>

<li>
Converting a slice of runes to a string type yields
a string that is the concatenation of the individual rune values
converted to strings.

<pre>
string([]rune{0x767d, 0x9d6c, 0x7fd4})   // "\u767d\u9d6c\u7fd4" == "白鵬翔"
string([]rune{})                         // ""
string([]rune(nil))                      // ""

type runes []rune

	<li>
	<code>x</code>'s type and <code>T</code> are both complex types.
	</li>
	<li>
	<code>x</code> is an integer or a slice of bytes or runes
	and <code>T</code> is a string type.
	</li>
	<li>
	<code>x</code> is a string and <code>T</code> is a slice of bytes or runes.
	</li>
	<li>
	<code>x</code> is a slice, <code>T</code> is a pointer to an array,