impl/65232 Adapt the existing comments model to be agnostic of News commentable (#19361)

https://community.openproject.org/work_packages/65232

app/models/comment.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #-- copyright
 # OpenProject is an open source project management software.
 # Copyright (C) the OpenProject GmbH
@@ -32,7 +34,7 @@ class Comment < ApplicationRecord
 
   validates :commented, :author, :comments, presence: true
 
-  after_create :send_news_comment_added_mail
+  after_create :send_comment_added_event
 
   def text
     comments
@@ -44,6 +46,10 @@ class Comment < ApplicationRecord
 
   private
 
+  def send_comment_added_event
+    send_news_comment_added_mail if commented_type == News.name
+  end
+
   def send_news_comment_added_mail
     OpenProject::Notifications.send(OpenProject::Events::NEWS_COMMENT_CREATED,
                                     comment: self,

spec/models/comment_spec.rb

@@ -32,12 +32,46 @@ require "spec_helper"
 RSpec.describe Comment do
   shared_let(:user) { create(:user) }
   shared_let(:news) { create(:news) }
-  let(:comment) { described_class.new(author: user, comments: "some important words", commented: news) }
+
+  let(:commented) { news }
+
+  subject(:comment) { build(:comment, author: user, comments: "some important words", commented:) }
+
+  describe "associations" do
+    it { is_expected.to belong_to(:author).class_name("User") }
+    it { is_expected.to belong_to(:commented) }
+  end
+
+  describe "validations" do
+    it { is_expected.to validate_presence_of(:author) }
+    it { is_expected.to validate_presence_of(:commented) }
+    it { is_expected.to validate_presence_of(:comments) }
+  end
 
   describe "#create" do
-    it "creates the comment" do
-      expect(described_class.create(commented: news, author: user, comments: "some important words"))
-        .to be_truthy
+    before do
+      allow(OpenProject::Notifications).to receive(:send)
+    end
+
+    context "for news" do
+      it "creates the comment" do
+        expect { comment.save! }
+          .to change(described_class, :count).by(1).and change { commented.reload.comments_count }.by(1)
+
+        aggregate_failures "sends a news comment added event" do
+          expect(OpenProject::Notifications).to have_received(:send)
+          .with(OpenProject::Events::NEWS_COMMENT_CREATED,
+                comment: comment, send_notification: true)
+        end
+      end
+    end
+  end
+
+  describe "#destroy" do
+    before { comment.save! }
+
+    it "decrements the comments_count on the commented object" do
+      expect { comment.destroy! }.to change { commented.reload.comments_count }.by(-1)
     end
   end