func (r *mockReader) Read(p []byte) (n int, err error) {
	if r.pos >= r.failAfter {
		return 0, fmt.Errorf("intentionally unexpected reader error")
	}
	r.pos++
	p[0] = r.mockData
	return 1, nil
}

func TestScannerFailure(t *testing.T) {
	var (
		i         int
		failAfter = 900
		mockData  = byte(32)
	)

	r := newMockReader(failAfter, mockData)
	scanner := newScanner(r)

	for i < 1000 {
		c := scanner.next()