Add merch_months_in with tests

lib/merch_calendar/date_calculator.rb

@@ -98,6 +98,18 @@ def julian_to_merch(julian_month)
       end
     end
 
-
+    def merch_months_in(start_date, end_date)
+      merch_months = []
+      prev_date = start_date - 2
+      date = start_date
+      while date <= end_date do
+        date = MerchCalendar.start_of_month(date.year, merch_month: date.month)
+        next if prev_date == date
+        merch_months.push(date)
+        prev_date = date
+        date += 14
+      end
+      merch_months
+    end
   end
-end
+end

lib/merch_calendar/util.rb

@@ -87,6 +87,16 @@ def weeks_in_year(year)
     end
 
 
+    # An array of merch dates in start_date to end_date
+    #
+    # @param start_date [Date] the start date
+    # @param end_date [Date] the end date
+    #
+    # @return [Array<Date>] array of merch months
+    def merch_months_in(start_date, end_date)
+      date_calc.merch_months_in(start_date, end_date)
+    end
+
 
     # Converts a merch month to the correct julian month
     #

spec/merch_calendar/date_calculator_spec.rb

@@ -48,5 +48,43 @@
 
   it "#end_of_quarter"
 
+  describe "#merch_months_in" do
+    it "returns merch date for start_date if start_date is the same as end_date" do
+      start_date = Date.new(2014,8,1)
+      end_date = start_date
+      start_merch_date = MerchCalendar.start_of_month(start_date.year, merch_month: start_date.month)
+
+      merch_months = subject.merch_months_in(start_date, end_date)
+      expect(merch_months.count).to be(1)
+      expect(merch_months.first.year).to eq start_merch_date.year
+      expect(merch_months.first.month).to eq start_merch_date.month
+      expect(merch_months.first.day).to eq start_merch_date.day
+    end
+
+    it "returns valid merch dates for 2014" do
+      start_date = Date.new(2014, 1, 1)
+      end_date = Date.new(2014, 12, 1)
+
+      merch_months = subject.merch_months_in(start_date, end_date)
+      expect(merch_months.count).to be 11
+
+      merch_months.each do |merch_month|
+        expect(merch_month.year).to be 2014
+      end
+
+      expect(merch_months[0].strftime('%Y-%m-%d')).to eq  '2014-02-02'
+      expect(merch_months[1].strftime('%Y-%m-%d')).to eq  '2014-03-02'
+      expect(merch_months[2].strftime('%Y-%m-%d')).to eq  '2014-04-06'
+      expect(merch_months[3].strftime('%Y-%m-%d')).to eq  '2014-05-04'
+      expect(merch_months[4].strftime('%Y-%m-%d')).to eq  '2014-06-01'
+      expect(merch_months[5].strftime('%Y-%m-%d')).to eq  '2014-07-06'
+      expect(merch_months[6].strftime('%Y-%m-%d')).to eq  '2014-08-03'
+      expect(merch_months[7].strftime('%Y-%m-%d')).to eq  '2014-08-31'
+      expect(merch_months[8].strftime('%Y-%m-%d')).to eq  '2014-10-05'
+      expect(merch_months[9].strftime('%Y-%m-%d')).to eq  '2014-11-02'
+      expect(merch_months[10].strftime('%Y-%m-%d')).to eq '2014-11-30'
+    end
+  end
+
 end