Add ActionCable::Connection::TestCase

[palkan]

Summary

Follow-up for #33659.

That's the final part of action-cable-testing merging.

Connection tests are written as follows:

1. First, one uses the connect method to simulate connection establishment (= connect callback invocation).
2. Then, one asserts whether the current state is as expected. "State" here means connection identifiers or whether connection has been authorized or not.

For example:

class ApplicationCable::Connection < ActionCable::Connection::Base
  identified_by :user_id

  def connect
    self.user_id = request.params[:user_id] || cookies.signed[:user_id]
    reject_unauthorized_connection if user_id.nil?
  end

  def disconnect
    ActionCable.server.broadcast "users_presence", { id: user_id, event: "left" }
  end
end

class ApplicationCable::ConnectionTest < ActionCable::Connection::TestCase
  def test_connects_with_params
    # Simulate a connection opening
    connect params: { user_id: 42 }

    assert_equal connection.user_id, "42"
  end

  def test_connects_with_cookies
    # the same API as for integrations tests
    cookies.signed[:user_id] = 42

    # just call connect without any arguments
    connect

    assert_equal connection.user_id, "42"
  end

  def test_reject_connection
    assert_reject_connection { connect }
  end
end

You can also specify cookies, headers, Rack–all the options available for integration tests–plus session

Other Information

This PR doesn't contain a changelog entry intentionally (as the previous two): I'll add a change log in another PR, in which I'd like to update a testing guide as well.

[sponomarev]

I wish that could be included to 5.2 branch.

[sponomarev]

I guess it makes sense to mention the support of signed/encrypted/plain cookies API, headers, env, and session in the documentation.

[sponomarev]

env and session options are missed here. cookies are no more an option

[sponomarev]

Am I right that this example is not relevant due to the new cookies API?

[sponomarev]

Ditto

[sponomarev]

❤️❤️❤️

[rmacklin]

👍 Great to see action-cable-testing making its way into rails core. Thanks for your continued work @palkan!

[palkan]

@rafaelfranca @kaspth Hey folks! Is there any chance for get this reviewed (and, hopefully, merged for Beta 1) and thus finish the action-cable-testing merging?

[kaspth]

I just saw the other comment and I have added this PR to my list! If all goes well, I'll get to this before beta1 🙏

[kaspth]

There we go, thanks @palkan!