A month input fields with a bad user input should make validity.badInput true and have :invalid style.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

Initial state. The elment has no value.
PASS colorOf(input) is not invalidStyleColor
PASS input.validity.badInput is false
Set a value to the first sub-field. The element becomes badInput.
PASS colorOf(input) is invalidStyleColor
PASS input.validity.badInput is true
PASS successfullyParsed is true

TEST COMPLETE