This is a testharness.js-based test.
[FAIL] Returns animations on pseudo-element when it is specified
  assert_equals: Returns one animation when the pseudo-element is specified expected 1 but got 0
[FAIL] Returns animations on functional pseudo-element when it is specified
  assert_equals: Returns one animation when the pseudo-element is specified expected 1 but got 0
[FAIL] The legacy Selectors Level 2 single-colon selectors can be used
  assert_equals: Returns one animation when the pseudo-element is specified by the legacy selector expected 1 but got 0
[FAIL] Throws SyntaxError for an invalid pseudo-element selector
  assert_throws_dom: function "() => {\n    div.getAnimations({ pseudoElement: ':invalid-pseudo' });\n  }" did not throw
[FAIL] Throws SyntaxError for an empty selector
  assert_throws_dom: function "() => {\n    div.getAnimations({ pseudoElement: '' });\n  }" did not throw
Harness: the test ran to completion.