;
  assert_false(single3.matches(":checked"),
      "single3 not :checked [after single1 checked]");

  single2.checked = true;
  assert_false(single1.checked, "single1 not checked [after single2 checked]");
  assert_false(single1.matches(":checked"),
      "single1 not :checked [after single2 checked]");
  assert_true(single2.checked, "single2 IS checked [after single1 checked]");
  assert_true(single2.matches(":checked"),
      "single2 IS :checked [after single2 checked]");
  assert_false(single3.checked