Re-implement today and yesterday methods

Using the by_day_Time_or_Date method

lib/by_star/by_day.rb

@@ -9,8 +9,15 @@ def by_day(*args)
     end
 
     def today(options={})
-      time = Time.zone.now
-      by_day_Time_or_Date(time, options)
+      by_day_Time_or_Date(Time.zone.now, options)
+    end
+
+    def yesterday(options={})
+      by_day_Time_or_Date(Time.zone.now.yesterday, options)
+    end
+
+    def tomorrow(options={})
+      by_day_Time_or_Date(Time.zone.now.tomorrow, options)
     end
 
     private

spec/by_star/by_day_spec.rb

@@ -32,3 +32,25 @@ def posts_count(*args)
     Event.today(:field => "start_time").size.should eql(1)
   end
 end
+
+describe "yesterday" do
+
+  it "should show the post for yesterday" do
+    Post.yesterday.map(&:text).should include("Yesterday")
+  end
+
+  it "should be able to use an alternative field" do
+    Event.yesterday(:field => "start_time").size.should eql(1)
+  end
+
+end
+
+describe "tomorrow" do
+  it "should show the post for tomorrow" do
+    Post.tomorrow.map(&:text).should include("Tomorrow's post")
+  end
+
+  it "should be able to use an alternative field" do
+    Event.tomorrow(:field => "start_time").size.should eql(1)
+  end
+end