Tests that the placeholder can be hidden and shown for empty fields via setCanShowPlaceholder().

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


Disallow showing of placeholder:
PASS internals.visiblePlaceholder(document.querySelector("input")) is ""
PASS internals.visiblePlaceholder(document.querySelector("textarea")) is ""

Allow showing of placeholder:
PASS internals.visiblePlaceholder(document.querySelector("input")) is "first"
PASS internals.visiblePlaceholder(document.querySelector("textarea")) is "second"
PASS successfullyParsed is true

TEST COMPLETE