keyframe-rule-cssom-modify-deleted-crash.html

<!DOCTYPE html>
<script src="../resources/testharness.js"></script>
<script src="../resources/testharnessreport.js"></script>
<style>
  @keyframes anim {
    50% { color: pink }
  }
</style>
<script>
  const anim = document.styleSheets[0].cssRules[0];
  const fifty = anim.cssRules[0];

  test(() => {
    assert_equals(anim.cssRules.length, 1);
    anim.deleteRule("50%");
    assert_equals(anim.cssRules.length, 0);
  }, "");

  test(() => {
    fifty.keyText = "10%";
  }, "Setting keyText on a removed keyframe should not crash.");

  test(() => {
    fifty.style.color = "green";
  }, "Setting style properties on a removed keyframe should not crash.");
</script>

chromium/third_party/blink/web_tests/animations/keyframe-rule-cssom-modify-deleted-crash.html