event: refactor as_json method and add a test

app/models/event.rb

@@ -99,23 +99,9 @@ class Event < ActiveRecord::Base
   def as_json(options)
     json = super(options)
 
-    if room.nil?
-      json[:room_guid] = nil
-    else
-      json[:room_guid] = room.guid
-    end
-
-    if track.nil?
-      json[:track_color]  = '#ffffff'
-    else
-      json[:track_color] = track.color
-    end
-
-    if event_type.nil?
-      json[:length] = 25
-    else
-      json[:length] = event_type.length
-    end
+    json[:room_guid] = room.try(:guid)
+    json[:track_color] = track.try(:color) || '#ffffff'
+    json[:length] = event_type.try(:length) || 25
 
     json
   end

spec/models/event_spec.rb

@@ -17,4 +17,27 @@ describe Event do
       expect(event.abstract_word_count).to eq(0)
     end
   end
+
+  describe 'as_json' do
+    let(:event) { create(:event) }
+
+    it 'adds the event\'s room_guid, track_color and length' do
+      event.room = create(:room)
+      event.track = create(:track, color: '#efefef')
+      json_hash = event.as_json(nil)
+
+      expect(json_hash[:room_guid]).to eq(event.room.guid)
+      expect(json_hash[:track_color]).to eq('#efefef')
+      expect(json_hash[:length]).to eq(30)
+    end
+
+    it 'uses correct default values for room_guid, track_color and length' do
+      event.event_type = nil
+      json_hash = event.as_json(nil)
+
+      expect(json_hash[:room_guid]).to be_nil
+      expect(json_hash[:track_color]).to eq('#ffffff')
+      expect(json_hash[:length]).to eq(25)
+    end
+  end
 end