System tests are used to test the application from the user's point of
view. To test for specific exceptions, particularly regarding
authorization permissions, controller tests fit better.
Another option would be to test the page displayed shows a certain text,
like "Internal server error". I'm choosing controller tests because
they're faster and we're basically testing the same scenario many times
and we've already got a test checking what happens when users access a
page raising an exception.
In theory it's possible to add a `host` parameter to a URL, and we could
end up redirecting to that host if we just redirect using query
parameters.
Generating the path using `url_for` with `only_path` solves the issue.
Note in the tests I'm using the `get` method because the `patch` method
wouldn't send query parameters. This doesn't mean the action can be
accessed through GET requests, since controller tests don't check route
verbs. Using feature specs doesn't seem to work because `controller` and
`host` parameters are filtered automatically in feature specs.
Also note I'm not testing every hidden/moderation controller because
they basically use the same code.
