JavaScript is used by about 98% of web users, so by testing without it
enabled, we're only testing that the application works for a very
reduced number of users.
We proceeded this way in the past because CONSUL started using Rails 4.2
and truncating the database between JavaScript tests with database
cleaner, which made these tests terribly slow.
When we upgraded to Rails 5.1 and introduced system tests, we started
using database transactions in JavaScript tests, making these tests much
faster. So now we can use JavaScript tests everywhere without critically
slowing down our test suite.
Rails automatically disables buttons when submitting a form. This works
fine most of the time: for AJAX requests, it enables them again after
the request is complete, and for non-AJAX requests, the button is
replaced by a new element when the new page loads.
However, there's an exception. When a request returns data so users can
download a fire, the request is not an AJAX one and the button is not
replaced. So users are left with a disabled button they can no longer
click.
So in this case, we aren't disabling the button after a user clicks it.
