assertThrows(IllegalStateException.class, () -> iterator.remove());
  }

  public void testSize0() {
    Iterator<String> iterator = emptyIterator();
    assertEquals(0, Iterators.size(iterator));
  }

  public void testSize1() {
    Iterator<Integer> iterator = singleton(0).iterator();
    assertEquals(1, Iterators.size(iterator));
  }

	{a: "abc\r\nabc", b: []string{"abc\r\n", "abc"}},
	{a: "abc\r\n", b: []string{"abc\r\n"}},
	{a: "\nabc", b: []string{"\n", "abc"}},
	{a: "\nabc\n\n", b: []string{"\n", "abc\n", "\n"}},
}

func TestLines(t *testing.T) {
	for _, s := range linesTests {
		result := sliceOfString(slices.Collect(Lines([]byte(s.a))))
		if !slices.Equal(result, s.b) {
			t.Errorf(`slices.Collect(Lines(%q)) = %q; want %q`, s.a, result, s.b)
		}