This is a testharness.js-based test.
Found 2 FAIL, 0 TIMEOUT, 0 NOTRUN.
[FAIL] animate() with a non-null invalid pseudoElement '' throws a SyntaxError
assert_throws_dom: function "() => {\n div.animate(null, {pseudoElement: pseudo});\n }" did not throw
[FAIL] animate() with a non-null invalid pseudoElement '::abc' throws a SyntaxError
assert_throws_dom: function "() => {\n div.animate(null, {pseudoElement: pseudo});\n }" did not throw
Harness: the test ran to completion.