Tests for ES6 arrow function lexical bind of arguments on top level On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS foo() threw exception ReferenceError: Can't find variable: arguments. PASS boo() threw exception ReferenceError: Can't find variable: arguments. PASS bar(true) threw exception ReferenceError: Can't find variable: arguments. PASS bar(false) is "no-error" PASS successfullyParsed is true TEST COMPLETE