Checking the database with methods like Activity.last does not test that
the record is present where it should be (first record of the table in
this case). In these tests there's only one record, though, so the order
doesn't matter that match.
However, calling methods like Activity.last generates a database query
after the process running the browser has been started, and this might
lead to inconsistent data.
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.
We've had a failure in one of our test suite runs [1]. A possible cause
could be an HTTP request taking place at the same time as an AJAX
request, with both trying to access the database at the same time.
We've had several similar issues in the past which have been fixed by
checking the AJAX request has finished before requesting another page,
so we're applying the same principle here.
[1] https://github.com/consul/consul/runs/1855207922
These tests were supposed to check the link to vote is hidden when users
don't have permission to vote. However, they aren't testing that, since
the `visible: false` option also matches visible elements. The links are
actually considered visible since they're displayed by the browser;
there's just another element on top of them.
Using `obscured: true` instead of `visible: false` solves the issue.
However, while the `obscured` option is true when the element is hidden
by another element, it's also true when the element is not currently
visible in the browser window, so in some cases we need to scroll so the
condition is effective.
