panic(err)
		}
	}()
	for count := 0; s.Scan(); count++ {
		if count > 1000 {
			t.Fatal("looping")
		}
	}
	if s.Err() != nil {
		t.Fatal("after scan:", s.Err())
	}
}

func TestBlankLines(t *testing.T) {
	s := NewScanner(strings.NewReader(strings.Repeat("\n", 1000)))
	for count := 0; s.Scan(); count++ {
		if count > 2000 {
			t.Fatal("looping")
		}
	}

	go func() {
		// We need the G continue running,
		// so the M has a chance to run this G.
		for {
			select {
			case <-stop:
				return
			case <-time.After(time.Millisecond * 100):
			}
		}
	}()
	defer close(stop)

	for i := 0; i < 1000; i++ {
		if !C.Ctid() {
			t.Fatalf("cgo has not locked OS thread")
		}
	}

type ScanToken rune

const (
	// Asm defines some two-character lexemes. We make up
	// a rune/ScanToken value for them - ugly but simple.
	LSH          ScanToken = -1000 - iota // << Left shift.
	RSH                                   // >> Logical right shift.
	ARR                                   // -> Used on ARM for shift type 3, arithmetic right shift.