Update broadcast_message helper

Now it returns the fully-formatted message so we can be consistent about
how it's shown.

spec/helpers/broadcast_messages_helper_spec.rb

@@ -1,22 +1,40 @@
 require 'spec_helper'
 
 describe BroadcastMessagesHelper do
-  describe 'broadcast_styling' do
-    let(:broadcast_message) { double(color: '', font: '') }
-
-    context "default style" do
-      it "should have no style" do
-        expect(broadcast_styling(broadcast_message)).to eq ''
-      end
+  describe 'broadcast_message' do
+    it 'returns nil when no current message' do
+      expect(helper.broadcast_message(nil)).to be_nil
     end
 
-    context "customized style" do
-      let(:broadcast_message) { double(color: "#f2dede", font: '#b94a48') }
+    it 'includes the current message' do
+      current = double(message: 'Current Message')
 
-      it "should have a customized style" do
-        expect(broadcast_styling(broadcast_message)).
-          to match('background-color: #f2dede; color: #b94a48')
-      end
+      allow(helper).to receive(:broadcast_message_style).and_return(nil)
+
+      expect(helper.broadcast_message(current)).to include 'Current Message'
+    end
+
+    it 'includes custom style' do
+      current = double(message: 'Current Message')
+
+      allow(helper).to receive(:broadcast_message_style).and_return('foo')
+
+      expect(helper.broadcast_message(current)).to include 'style="foo"'
+    end
+  end
+
+  describe 'broadcast_message_style' do
+    it 'defaults to no style' do
+      broadcast_message = spy
+
+      expect(helper.broadcast_message_style(broadcast_message)).to eq ''
+    end
+
+    it 'allows custom style' do
+      broadcast_message = double(color: '#f2dede', font: '#b94a48')
+
+      expect(helper.broadcast_message_style(broadcast_message)).
+        to match('background-color: #f2dede; color: #b94a48')
     end
   end
 end