ActionCable::Channel::TestCase

Superclass for Action Cable channel functional tests.

## Basic example

Functional tests are written as follows:

1. First, one uses the `subscribe` method to simulate subscription creation.

2. Then, one asserts whether the current state is as expected. “State” can be anything: transmitted messages, subscribed streams, etc.

For example:

class ChatChannelTest < ActionCable::Channel::TestCase
  def test_subscribed_with_room_number
    # Simulate a subscription creation
    subscribe room_number: 1

    # Asserts that the subscription was successfully created
    assert subscription.confirmed?

    # Asserts that the channel subscribes connection to a stream
    assert_has_stream "chat_1"

    # Asserts that the channel subscribes connection to a specific
    # stream created for a model
    assert_has_stream_for Room.find(1)
  end

  def test_does_not_stream_with_incorrect_room_number
    subscribe room_number: -1

    # Asserts that not streams was started
    assert_no_streams
  end

  def test_does_not_subscribe_without_room_number
    subscribe

    # Asserts that the subscription was rejected
    assert subscription.rejected?
  end
end

You can also perform actions:

def test_perform_speak
  subscribe room_number: 1

  perform :speak, message: "Hello, Rails!"

  assert_equal "Hello, Rails!", transmissions.last["text"]
end

## Special methods

ActionCable::Channel::TestCase will also automatically provide the following instance methods for use in the tests:

connection : An ActionCable::Channel::ConnectionStub, representing the current HTTP

connection.

subscription : An instance of the current channel, created when you call `subscribe`.

transmissions : A list of all messages that have been transmitted into the channel.

## Channel is automatically inferred

ActionCable::Channel::TestCase will automatically infer the channel under test from the test class name. If the channel cannot be inferred from the test class name, you can explicitly set it with `tests`.

class SpecialEdgeCaseChannelTest < ActionCable::Channel::TestCase
  tests SpecialChannel
end

## Specifying connection identifiers

You need to set up your connection manually to provide values for the identifiers. To do this just use:

stub_connection(user: users(:john))

## Testing broadcasting

ActionCable::Channel::TestCase enhances ActionCable::TestHelper assertions (e.g. `assert_broadcasts`) to handle broadcasting to models:

# in your channel
def speak(data)
  broadcast_to room, text: data["message"]
end

def test_speak
  subscribe room_id: rooms(:chat).id

  assert_broadcast_on(rooms(:chat), text: "Hello, Rails!") do
    perform :speak, message: "Hello, Rails!"
  end
end