That would allow us to test broadcasting made with channel, e.g.:
```ruby
class ChatRelayJob < ApplicationJob
def perform_later(room, msg)
ChatChannel.broadcast_to room, message: msg
end
end
```
To test this functionality we need to know the underlying stream name
(to use `assert_broadcasts`), which relies on `channel_name`.
We had to use the following code:
```ruby
assert_broadcasts(ChatChannel.broadcasting_for([ChatChannel.channel_name, room]), 1) do
ChatRelayJob.perform_now
end
```
The problem with this approach is that we use _internal_ API (we shouldn't care about `channel_name` prefix
in our code).
With this commit we could re-write the test as following:
```ruby
assert_broadcasts(ChatChannel.broadcasting_for(room), 1) do
ChatRelayJob.perform_now
end
```
The hack was merged from action-cable-testing gem by mistake.
We don't need it in Rails 6.
(cherry picked from commit 92030ec4b4309835ed0e792229984a1f0a044cef)
ActionCable::Channel::TestCase provides an ability
to unit-test channel classes.
There are several reasons to write unit/functional cable tests:
- Access control (who has access to the channel? who can perform action and with which argument?
- Frontend-less applications have no system tests at all–and we still need a way to test channels logic.
See also #27191
