Refactor formatter (#17828)

* Refactor formatter

* Move custom emoji pre-rendering logic to view helpers

* Move more methods out of Formatter

* Fix code style issues

* Remove Formatter

* Add inline poll options to RSS feeds

* Remove unused helper method

* Fix code style issues

* Various fixes and improvements

* Fix test

spec/lib/emoji_formatter_spec.rb

@@ -0,0 +1,55 @@
+require 'rails_helper'
+
+RSpec.describe EmojiFormatter do
+  let!(:emoji) { Fabricate(:custom_emoji, shortcode: 'coolcat') }
+
+  def preformat_text(str)
+    TextFormatter.new(str).to_s
+  end
+
+  describe '#to_s' do
+    subject { described_class.new(text, emojis).to_s }
+
+    let(:emojis) { [emoji] }
+
+    context 'given text that is not marked as html-safe' do
+      let(:text) { 'Foo' }
+
+      it 'raises an argument error' do
+        expect { subject }.to raise_error ArgumentError
+      end
+    end
+
+    context 'given text with an emoji shortcode at the start' do
+      let(:text) { preformat_text(':coolcat: Beep boop') }
+
+      it 'converts the shortcode to an image tag' do
+        is_expected.to match(/<img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+      end
+    end
+
+    context 'given text with an emoji shortcode in the middle' do
+      let(:text) { preformat_text('Beep :coolcat: boop') }
+
+      it 'converts the shortcode to an image tag' do
+        is_expected.to match(/Beep <img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+      end
+    end
+
+    context 'given text with concatenated emoji shortcodes' do
+      let(:text) { preformat_text(':coolcat::coolcat:') }
+
+      it 'does not touch the shortcodes' do
+        is_expected.to match(/:coolcat::coolcat:/)
+      end
+    end
+
+    context 'given text with an emoji shortcode at the end' do
+      let(:text) { preformat_text('Beep boop :coolcat:') }
+
+      it 'converts the shortcode to an image tag' do
+        is_expected.to match(/boop <img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+      end
+    end
+  end
+end