Test how setCustomValidity reacts to too few arguments.
On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
PASS b.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLButtonElement': 1 argument required, but only 0 present..
PASS fs.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLFieldSetElement': 1 argument required, but only 0 present..
PASS i.setCustomValidity() threw exception TypeError: Failed to execute 'setCustomValidity' on 'HTMLInputElement': 1 argument required, but only 0 present..
PASS successfullyParsed is true
TEST COMPLETE