Fix 0.business_days and 0.business_hours calculation

lib/business_time/business_days.rb

@@ -17,23 +17,23 @@ def <=>(other)
     end
 
     def after(time = Time.current)
-      positive_days? ? calculate_after(time, @days) : calculate_before(time, -@days)
+      non_negative_days? ? calculate_after(time, @days) : calculate_before(time, -@days)
     end
 
     alias_method :from_now, :after
     alias_method :since, :after
 
     def before(time = Time.current)
-      positive_days? ? calculate_before(time, @days) : calculate_after(time, -@days)
+      non_negative_days? ? calculate_before(time, @days) : calculate_after(time, -@days)
     end
 
     alias_method :ago, :before
     alias_method :until, :before
 
     private
 
-    def positive_days?
-      @days > 0
+    def non_negative_days?
+      @days >= 0
     end
 
     def calculate_after(time, days)

lib/business_time/business_hours.rb

@@ -24,18 +24,18 @@ def from_now
     end
 
     def after(time)
-      positive_hours? ? calculate_after(time, @hours) : calculate_before(time, -@hours)
+      non_negative_hours? ? calculate_after(time, @hours) : calculate_before(time, -@hours)
     end
     alias_method :since, :after
 
     def before(time)
-      positive_hours? ? calculate_before(time, @hours) : calculate_after(time, -@hours)
+      non_negative_hours? ? calculate_before(time, @hours) : calculate_after(time, -@hours)
     end
 
     private
 
-    def positive_hours?
-      @hours > 0
+    def non_negative_hours?
+      @hours >= 0
     end
 
     def calculate_after(time, hours)

test/test_business_days.rb

@@ -17,6 +17,13 @@
         assert_equal expected, after
       end
 
+      it "should pick next working day when adding zero days on the weekend" do
+        first = Time.parse("April 10th, 2010, 12:33 pm")
+        after = 0.business_days.after(first)
+        expected = Time.parse("April 12th, 2010, 12:33 pm")
+        assert_equal expected, after
+      end
+
       it "should move forward one week when adding 5 business days" do
         first = Time.parse("April 9th, 2010, 12:33 pm")
         after = 5.business_days.after(first)

test/test_business_hours.rb

@@ -24,6 +24,13 @@
         assert_equal expected, monday_morning
       end
 
+      it "picks next working day when adding zero hours on weekends" do
+        first = Time.parse("April 10th, 2010, 12:33 pm")
+        after = 0.business_hours.after(first)
+        expected = Time.parse("April 12th, 2010, 9:00 am")
+        assert_equal expected, after
+      end
+
       it "take into account a weekend when adding an hour, using the common interface #since" do
         friday_afternoon = Time.parse("April 9th 2010, 4:50 pm")
         monday_morning = 1.business_hour.since(friday_afternoon)