add volunteers helper

spec/helpers/events_helper_spec.rb

@@ -0,0 +1,21 @@
+require 'spec_helper'
+
+describe EventsHelper, type: :helper do
+  let(:conference) { create(:conference) }
+  let(:event) { create(:event, program: conference.program) }
+
+  describe '#registered_text' do
+    describe 'returns correct string' do
+      it 'when there are no registrations' do
+        expect(registered_text(event)).to eq 'Registered: 0'
+      end
+
+      it 'when there is 1 registration' do
+        event.require_registration = true
+        event.max_attendees = 3
+        event.registrations << create(:registration, user: event.submitter)
+        expect(registered_text(event)).to eq 'Registered: 1/3'
+      end
+    end
+  end
+end