The `sign_in(nil)` method was a bit hard to understand IMHO. After all,
in controller and system tests we don't have to specify no user is
signed in; that's the default behavior.
So we're making it the default behavior for component tests as well.
When render the investment list component with the link "see all
investments", now we redirect to groups index page when a budget has
multiple headings.
In general, slow system tests requiring no interaction from the user are
good candidates to be moved to component tests because component tests
are much faster.
In this case, the system tests were also updating the database after
starting the browser, which might cause concurrency issues. We could
split the test and have one system test per phase, but IMHO there's no
need.
We're still having a couple of system tests for the happy path, in order
to make sure users actually see the list of investments.
Note one of the tests dealing with random results is a bit flaky; since
it's a permutation selecting 7 objects out of 12, it will fail about
once every 4 million times. We think this is acceptable.
Co-Authored-By: Julian Nicolas Herrero <microweb10@gmail.com>
