Smart broadcast_to matcher (palkan#10)

Accept objects as arguments for `broadcast_to` RSpec matcher.
Add optional `from_channel` modifier.

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Change log
 
+## (2017-11-27) ([@thesmartnik][])
+
+- Update `have_broadcasted_to` matcher to support a record as an argument.
+
+See https://github.com/palkan/action-cable-testing/issues/9
+
 ## 0.1.2 (2017-11-14) ([@palkan][])
 
 - Add RSpec shared contexts to switch between adapters.
@@ -15,3 +21,4 @@ See https://github.com/palkan/action-cable-testing/issues/4.
 - Initial version. ([@palkan][])
 
 [@palkan]: https://github.com/palkan
+[@thesmartnik]: https://github.com/thesmartnik

README.md

@@ -152,6 +152,19 @@ RSpec.describe CommentsController do
 end
 ```
 
+Or when broacasting to an object:
+
+```ruby
+RSpec.describe CommentsController do
+ describe "POST #create" do
+ let(:post) { create :post }
+
+ expect { post :create, comment: { text: 'Cool!', post_id: post.id } }.to
+ have_broadcasted_to(post).from_channel(PostChannel).with(text: 'Cool!')
+ end
+end
+```
+
 You can also unit-test your channels:
 
 

features/matchers/have_broadcasted_matcher.feature

@@ -97,3 +97,29 @@ Feature: have_broadcasted matcher
  """
  When I run `rspec spec/models/broadcaster_spec.rb`
  Then the examples should all pass
+
+ Scenario: Checking broadcast to a record
+ Given a file named "spec/channels/chat_channel_spec.rb" with:
+ """ruby
+ require "rails_helper"
+
+ RSpec.describe ChatChannel, :type => :channel do
+ it "successfully subscribes" do
+ user = User.new(42)
+
+ expect {
+ ChatChannel.broadcast_to(user, text: 'Hi')
+ }.to have_broadcasted_to(user)
+ end
+ end
+ """
+ And a file named "app/models/user.rb" with:
+ """ruby
+ class User < Struct.new(:name)
+ def to_global_id
+ name
+ end
+ end
+ """
+ When I run `rspec spec/channels/chat_channel_spec.rb`
+ Then the example should pass

lib/rspec/rails/matchers/action_cable.rb

@@ -10,8 +10,9 @@ module ActionCable
  # rubocop: disable Style/ClassLength
  # @private
  class HaveBroadcastedTo < RSpec::Matchers::BuiltIn::BaseMatcher
- def initialize(stream)
- @stream = stream
+ def initialize(target, channel:)
+ @target = target
+ @channel = channel
  @block = Proc.new {}
  set_expected_number(:exactly, 1)
  end
@@ -57,7 +58,7 @@ def thrice
  def failure_message
  "expected to broadcast #{base_message}".tap do |msg|
  if @unmatching_msgs.any?
- msg << "\nBroadcasted messages to #{@stream}:"
+ msg << "\nBroadcasted messages to #{stream}:"
  @unmatching_msgs.each do |data|
  msg << "\n #{data}"
  end
@@ -84,15 +85,29 @@ def supports_block_expectations?
  def matches?(proc)
  raise ArgumentError, "have_broadcasted_to and broadcast_to only support block expectations" unless Proc === proc
 
- original_sent_messages_count = pubsub_adapter.broadcasts(@stream).size
+ original_sent_messages_count = pubsub_adapter.broadcasts(stream).size
  proc.call
- in_block_messages = pubsub_adapter.broadcasts(@stream).drop(original_sent_messages_count)
+ in_block_messages = pubsub_adapter.broadcasts(stream).drop(original_sent_messages_count)
 
  check(in_block_messages)
  end
 
+ def from_channel(channel)
+ @channel = channel
+ self
+ end
+
  private
 
+ def stream
+ @stream ||= if @target.is_a?(String)
+ @target
+ else
+ check_channel_presence
+ @channel.broadcasting_for([@channel.channel_name, @target])
+ end
+ end
+
  def check(messages)
  @matching_msgs, @unmatching_msgs = messages.partition do |msg|
  decoded = ActiveSupport::JSON.decode(msg)
@@ -127,7 +142,7 @@ def set_expected_number(relativity, count)
  end
 
  def base_message
- "#{message_expectation_modifier} #{@expected_number} messages to #{@stream}".tap do |msg|
+ "#{message_expectation_modifier} #{@expected_number} messages to #{stream}".tap do |msg|
  msg << " with #{data_description(@data)}" unless @data.nil?
  msg << ", but broadcast #{@matching_msgs_count}"
  end
@@ -144,18 +159,32 @@ def data_description(data)
  def pubsub_adapter
  ::ActionCable.server.pubsub
  end
+
+ def check_channel_presence
+ return if @channel.present? && @channel.respond_to?(:channel_name)
+
+ error_msg = "Broadcastnig channel can't be infered. Please, specify it with `from_channel`"
+ raise ArgumentError, error_msg
+ end
  end
  # rubocop: enable Style/ClassLength
  end
 
  # @api public
- # Passes if a message has been sent to a stream inside block. May chain at_least, at_most or exactly to specify a number of times.
+ # Passes if a message has been sent to a stream/object inside a block.
+ # May chain `at_least`, `at_most` or `exactly` to specify a number of times.
+ # To specify channel from which message has been broadcasted to object use `from_channel`.
+ #
  #
  # @example
  # expect {
  # ActionCable.server.broadcast "messages", text: 'Hi!'
  # }.to have_broadcasted_to("messages")
  #
+ # expect {
+ # SomeChannel.broadcast_to(user)
+ # }.to have_broadcasted_to(user).from_channel(SomeChannel)
+ #
  # # Using alias
  # expect {
  # ActionCable.server.broadcast "messages", text: 'Hi!'
@@ -177,9 +206,11 @@ def pubsub_adapter
  # expect {
  # ActionCable.server.broadcast "messages", text: 'Hi!'
  # }.to have_broadcasted_to("messages").with(text: 'Hi!')
- def have_broadcasted_to(stream = nil)
+
+ def have_broadcasted_to(target = nil)
  check_action_cable_adapter
- ActionCable::HaveBroadcastedTo.new(stream)
+
+ ActionCable::HaveBroadcastedTo.new(target, channel: described_class)
  end
  alias_method :broadcast_to, :have_broadcasted_to
 

spec/rspec/rails/matchers/action_cable_spec.rb

@@ -5,6 +5,9 @@
  require "rspec/rails/matchers/action_cable"
 end
 
+class BroadcastToChannel < ActionCable::Channel::Base
+end
+
 RSpec.describe "ActionCable matchers", :skip => !RSpec::Rails::FeatureCheck.has_action_cable? do
  def broadcast(stream, msg)
  ActionCable.server.broadcast stream, msg
@@ -171,5 +174,28 @@ def broadcast(stream, msg)
  expect(e.message).to match(/got: "asdf"/)
  }
  end
+
+
+ context "when object is passed as first argument" do
+ let(:user) { User.new(42) }
+
+ context "when channel is present" do
+ it "passes" do
+ expect {
+ BroadcastToChannel.broadcast_to(user, text: 'Hi')
+ }.to have_broadcasted_to(user).from_channel(BroadcastToChannel)
+ end
+ end
+
+ context "when channel can't be infered" do
+ it "raises exception" do
+ expect {
+ expect {
+ BroadcastToChannel.broadcast_to(user, text: 'Hi')
+ }.to have_broadcasted_to(user)
+ }.to raise_error(ArgumentError)
+ end
+ end
+ end
  end
 end