Add ActionCable::Channel::TestCase

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

1 files changed, 188 insertions, 0 deletions

diff --git a/actioncable/test/channel/test_case_test.rb b/actioncable/test/channel/test_case_test.rb
new file mode 100644
index 0000000000..63d0d6207e
--- /dev/null
+++ b/actioncable/test/channel/test_case_test.rb
@@ -0,0 +1,188 @@
+# frozen_string_literal: true
+
+require "test_helper"
+
+class TestTestChannel < ActionCable::Channel::Base
+end
+
+class NonInferrableExplicitClassChannelTest < ActionCable::Channel::TestCase
+  tests TestTestChannel
+
+  def test_set_channel_class_manual
+    assert_equal TestTestChannel, self.class.channel_class
+  end
+end
+
+class NonInferrableSymbolNameChannelTest < ActionCable::Channel::TestCase
+  tests :test_test_channel
+
+  def test_set_channel_class_manual_using_symbol
+    assert_equal TestTestChannel, self.class.channel_class
+  end
+end
+
+class NonInferrableStringNameChannelTest < ActionCable::Channel::TestCase
+  tests "test_test_channel"
+
+  def test_set_channel_class_manual_using_string
+    assert_equal TestTestChannel, self.class.channel_class
+  end
+end
+
+class SubscriptionsTestChannel < ActionCable::Channel::Base
+end
+
+class SubscriptionsTestChannelTest < ActionCable::Channel::TestCase
+  def setup
+    stub_connection
+  end
+
+  def test_no_subscribe
+    assert_nil subscription
+  end
+
+  def test_subscribe
+    subscribe
+
+    assert subscription.confirmed?
+    assert_not subscription.rejected?
+    assert_equal 1, connection.transmissions.size
+    assert_equal ActionCable::INTERNAL[:message_types][:confirmation],
+                 connection.transmissions.last["type"]
+  end
+end
+
+class StubConnectionTest < ActionCable::Channel::TestCase
+  tests SubscriptionsTestChannel
+
+  def test_connection_identifiers
+    stub_connection username: "John", admin: true
+
+    subscribe
+
+    assert_equal "John", subscription.username
+    assert subscription.admin
+  end
+end
+
+class RejectionTestChannel < ActionCable::Channel::Base
+  def subscribed
+    reject
+  end
+end
+
+class RejectionTestChannelTest < ActionCable::Channel::TestCase
+  def test_rejection
+    subscribe
+
+    assert_not subscription.confirmed?
+    assert subscription.rejected?
+    assert_equal 1, connection.transmissions.size
+    assert_equal ActionCable::INTERNAL[:message_types][:rejection],
+                 connection.transmissions.last["type"]
+  end
+end
+
+class StreamsTestChannel < ActionCable::Channel::Base
+  def subscribed
+    stream_from "test_#{params[:id] || 0}"
+  end
+end
+
+class StreamsTestChannelTest < ActionCable::Channel::TestCase
+  def test_stream_without_params
+    subscribe
+
+    assert_equal "test_0", streams.last
+  end
+
+  def test_stream_with_params
+    subscribe id: 42
+
+    assert_equal "test_42", streams.last
+  end
+end
+
+class PerformTestChannel < ActionCable::Channel::Base
+  def echo(data)
+    data.delete("action")
+    transmit data
+  end
+
+  def ping
+    transmit type: "pong"
+  end
+end
+
+class PerformTestChannelTest < ActionCable::Channel::TestCase
+  def setup
+    stub_connection user_id: 2016
+    subscribe id: 5
+  end
+
+  def test_perform_with_params
+    perform :echo, text: "You are man!"
+
+    assert_equal({ "text" => "You are man!" }, transmissions.last)
+  end
+
+  def test_perform_and_transmit
+    perform :ping
+
+    assert_equal "pong", transmissions.last["type"]
+  end
+end
+
+class PerformUnsubscribedTestChannelTest < ActionCable::Channel::TestCase
+  tests PerformTestChannel
+
+  def test_perform_when_unsubscribed
+    assert_raises do
+      perform :echo
+    end
+  end
+end
+
+class BroadcastsTestChannel < ActionCable::Channel::Base
+  def broadcast(data)
+    ActionCable.server.broadcast(
+      "broadcast_#{params[:id]}",
+      text: data["message"], user_id: user_id
+    )
+  end
+
+  def broadcast_to_user(data)
+    user = User.new user_id
+
+    self.class.broadcast_to user, text: data["message"]
+  end
+end
+
+class BroadcastsTestChannelTest < ActionCable::Channel::TestCase
+  def setup
+    stub_connection user_id: 2017
+    subscribe id: 5
+  end
+
+  def test_broadcast_matchers_included
+    assert_broadcast_on("broadcast_5", user_id: 2017, text: "SOS") do
+      perform :broadcast, message: "SOS"
+    end
+  end
+
+  def test_broadcast_to_object
+    user = User.new(2017)
+
+    assert_broadcasts(user, 1) do
+      perform :broadcast_to_user, text: "SOS"
+    end
+  end
+
+  def test_broadcast_to_object_with_data
+    user = User.new(2017)
+
+    assert_broadcast_on(user, text: "SOS") do
+      perform :broadcast_to_user, message: "SOS"
+    end
+  end
+end