Spec coverage for custom css endpoint (mastodon#28706)

app/controllers/custom_css_controller.rb

@@ -1,8 +1,21 @@
 # frozen_string_literal: true
 
 class CustomCssController < ActionController::Base # rubocop:disable Rails/ApplicationController
+  before_action :set_user_roles
+
   def show
     expires_in 3.minutes, public: true
     render content_type: 'text/css'
   end
+
+  private
+
+  def custom_css_styles
+    Setting.custom_css
+  end
+  helper_method :custom_css_styles
+
+  def set_user_roles
+    @user_roles = UserRole.where(highlighted: true).where.not(color: [nil, ''])
+  end
 end

app/views/custom_css/show.css.erb

@@ -1,8 +1,8 @@
-<%- if Setting.custom_css.present? %>
-<%= raw Setting.custom_css %>
+<%- if custom_css_styles.present? %>
+<%= raw custom_css_styles %>
 
 <%- end %>
-<%- UserRole.where(highlighted: true).select { |role| role.color.present? }.each do |role| %>
+<%- @user_roles.each do |role| %>
 .user-role-<%= role.id %> {
   --user-role-accent: <%= role.color %>;
 }

spec/requests/custom_css_spec.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Custom CSS' do
+  include RoutingHelper
+
+  describe 'GET /custom.css' do
+    context 'without any CSS or User Roles' do
+      it 'returns empty stylesheet' do
+        get '/custom.css'
+
+        expect(response.content_type).to include('text/css')
+        expect(response.body.presence).to be_nil
+      end
+    end
+
+    context 'with CSS settings' do
+      before do
+        Setting.custom_css = expected_css
+      end
+
+      it 'returns stylesheet from settings' do
+        get '/custom.css'
+
+        expect(response.content_type).to include('text/css')
+        expect(response.body.strip).to eq(expected_css)
+      end
+
+      def expected_css
+        <<~CSS.strip
+          body { background-color: red; }
+        CSS
+      end
+    end
+
+    context 'with highlighted colored UserRole records' do
+      before do
+        _highlighted_colored = Fabricate :user_role, highlighted: true, color: '#336699', id: '123_123_123'
+        _highlighted_no_color = Fabricate :user_role, highlighted: true, color: ''
+        _no_highlight_with_color = Fabricate :user_role, highlighted: false, color: ''
+      end
+
+      it 'returns stylesheet from settings' do
+        get '/custom.css'
+
+        expect(response.content_type).to include('text/css')
+        expect(response.body.strip).to eq(expected_css)
+      end
+
+      def expected_css
+        <<~CSS.strip
+          .user-role-123123123 {
+            --user-role-accent: #336699;
+          }
+        CSS
+      end
+    end
+  end
+end