Merge pull request #81 from thegcat/decorator_spec

Calculation spec

app/decorators/activity_decorator.rb

@@ -34,14 +34,18 @@ def requirements_markdown
   def room_left
     if object.anybody_can_join? then ""
     else
-      left = [[object.limit_of_participants - object.participations_count, 0].max, object.limit_of_participants ].min
+      left = open_spots
       if    left == 1 then I18n.t("activities.room_left.one")
       elsif left >  0 then I18n.t("activities.room_left.many", left: left)
       else                 I18n.t("activities.room_left.none")
       end
     end
   end
 
+  def open_spots
+    [[object.limit_of_participants - object.participations_count, 0].max, object.limit_of_participants ].min
+  end
+
   def time
     if object.anytime?
       I18n.t("activities.anytime")

spec/decorators/activity_decorator_spec.rb

@@ -1,4 +1,39 @@
 require 'spec_helper'
 
 describe ActivityDecorator do
+  let (:activity) { FactoryGirl.build_stubbed(:activity, limit_of_participants: 20) }
+  let (:decorator) { ActivityDecorator.new(activity) }
+
+  describe "#spots_left" do
+    subject { decorator.open_spots }
+
+    before do
+      activity.stub(:participations_count).and_return(count)
+    end
+
+    context "no participants" do
+      let(:count) { 0 }
+
+      it { should == 20 }
+    end
+
+    context "some participants" do
+      let(:count) { 5 }
+
+      it { should == 15 }
+    end
+
+    context "too many participants" do
+      let(:count) { 25 }
+
+      it { should == 0 }
+    end
+
+    context "you're drunk Rails, go home!" do
+      # it seems Rails counter caches return negative values sometimes
+      let(:count) { -5 }
+
+      it { should == 20 }
+    end
+  end
 end