Add test for base broadcaster

.gitignore

@@ -9,3 +9,4 @@ tmp/
 node_modules
 .vscode
 /javascript/dist
+*~

lib/stimulus_reflex/broadcasters/broadcaster.rb

@@ -9,7 +9,7 @@ class Broadcaster
 
     def initialize(reflex)
       @reflex = reflex
-      @logger = Rails.logger
+      @logger = Rails.logger if defined?(Rails.logger)
     end
 
     def nothing?

test/broadcasters/broadcaster_test.rb

@@ -0,0 +1,15 @@
+require_relative "../test_helper"
+
+class StimulusReflex::BroadcasterTest < ActiveSupport::TestCase
+  setup do
+    @reflex = Minitest::Mock.new
+    @reflex.expect :stream_name, "TestStream"
+  end
+
+  test "raises a NotImplementedError if called directly" do
+    broadcaster = StimulusReflex::Broadcaster.new(@reflex)
+
+    assert_raises(NotImplementedError) { broadcaster.broadcast }
+    assert_raises(NotImplementedError) { broadcaster.broadcast_message(subject: "Test") }
+  end
+end

test/test_helper.rb

@@ -1,4 +1,6 @@
 # frozen_string_literal: true
 
+require "minitest/mock"
+
 ENV["RAILS_ENV"] ||= "test"
 require_relative "../lib/stimulus_reflex"