This is a testharness.js-based test.
Found 2 FAIL, 0 TIMEOUT, 0 NOTRUN.
[FAIL] Should throw NOT_SUPPORTED_ERR for pluralized legacy event interface "KeyboardEvents"
  assert_throws_dom: function "function () {\n          var evt = document.createEvent(plural);\n        }" did not throw
[FAIL] Should throw NOT_SUPPORTED_ERR for non-legacy event interface "TransitionEvent"
  assert_throws_dom: function "function () {\n      var evt = document.createEvent(eventInterface);\n    }" did not throw
Harness: the test ran to completion.