Add tests for admin/roles_controller (#7421)

spec/controllers/admin/roles_controller_spec.rb

+require 'rails_helper'
+
+describe Admin::RolesController do
+  render_views
+
+  let(:admin) { Fabricate(:user, admin: true) }
+
+  before do
+    sign_in admin, scope: :user
+  end
+
+  describe 'POST #promote' do
+    subject { post :promote, params: { account_id: user.account_id } }
+
+    let(:user) { Fabricate(:user, moderator: false, admin: false) }
+
+    it 'promotes user' do
+      expect(subject).to redirect_to admin_account_path(user.account_id)
+      expect(user.reload).to be_moderator
+    end
+  end
+
+  describe 'POST #demote' do
+    subject { post :demote, params: { account_id: user.account_id } }
+
+    let(:user) { Fabricate(:user, moderator: true, admin: false) }
+
+    it 'demotes user' do
+      expect(subject).to redirect_to admin_account_path(user.account_id)
+      expect(user.reload).not_to be_moderator
+    end
+  end
+end