Avoid StopIteration leak on explicit #next call in #next_occurrence

[#203]
[#213]

lib/ice_cube/schedule.rb

@@ -174,7 +174,11 @@ def next_occurrences(num, from = nil)
     # The next occurrence after now (overridable)
     def next_occurrence(from = nil)
       from ||= TimeUtil.now(@start_time)
-      enumerate_occurrences(from + 1, nil).next()
+      begin
+        enumerate_occurrences(from + 1, nil).next()
+      rescue StopIteration
+        nil
+      end
     end
 
     # The previous occurrence from a given time
@@ -210,13 +214,12 @@ def occurrences_between(begin_time, closing_time)
 
     # Return a boolean indicating if an occurrence falls between two times
     def occurs_between?(begin_time, closing_time)
-      begin 
+      begin
         enumerate_occurrences(begin_time, closing_time).next()
         true
       rescue StopIteration
         false
       end
-
     end
 
     # Return a boolean indicating if an occurrence is occurring between two

spec/examples/schedule_spec.rb

@@ -26,6 +26,15 @@
     schedule.start_time.should == Time.local(dt.year, dt.month, dt.day, dt.hour, dt.min, dt.sec)
   end
 
+  describe :next_occurrence do
+
+    it 'should not raise an exception when calling next occurrence with no remaining occurrences' do
+      schedule = IceCube::Schedule.new Time.now
+      lambda { schedule.next_occurrence }.should_not raise_error
+    end
+
+  end
+
   describe :duration do
 
     it 'should be based on end_time' do