c += 'a' - 'A'
	}
	return
}

func (d *downCaser) Read(p []byte) (int, error) {
	d.t.Fatalf("unexpected Read call on downCaser reader")
	panic("unreachable")
}

func TestRawTokenAltEncoding(t *testing.T) {
	d := NewDecoder(strings.NewReader(testInputAltEncoding))
	d.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {
		if charset != "x-testing-uppercase" {