Time#- coerces TimeWithZone argument to a Time instance so that difference in seconds can be calculated. Closes #10914 [Geoff Buesing, yyyc514]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8730 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

4 files changed, 27 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 40ddbf473e..3883925fc8 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Time#- coerces TimeWithZone argument to a Time instance so that difference in seconds can be calculated. Closes #10914 [Geoff Buesing, yyyc514]
+
 * Adding UTC zone to TimeZone; TimeWithZone no longer has to fake UTC zone with nil [Geoff Buesing]
 
 * Time.get_zone refactored to private method, given that the encapsulated logic is only useful internally [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index eb342084a8..7fbfca5b2a 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -13,6 +13,9 @@ module ActiveSupport #:nodoc:
             alias_method :minus_without_duration, :-
             alias_method :-, :minus_with_duration
             
+            alias_method :minus_without_coercion, :-
+            alias_method :-, :minus_with_coercion
+            
             alias_method :compare_without_coercion, :<=>
             alias_method :<=>, :compare_with_coercion
           end
@@ -218,6 +221,14 @@ module ActiveSupport #:nodoc:
           end
         end
         
+        # Time#- can also be used to determine the number of seconds between two Time instances.
+        # We're layering on additional behavior so that ActiveSupport::TimeWithZone instances
+        # are coerced into values that Time#- will recognize
+        def minus_with_coercion(other)
+          other = other.comparable_time if other.respond_to?(:comparable_time)
+          minus_without_coercion(other)
+        end
+        
         # Layers additional behavior on Time#<=> so that DateTime and ActiveSupport::TimeWithZone instances
         # can be chronologically compared with a Time
         def compare_with_coercion(other)
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 2377d3c63c..fef8a521da 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -454,6 +454,10 @@ class TimeExtCalculationsTest < Test::Unit::TestCase
     assert_equal  0, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 0), TimeZone['UTC'] )
     assert_equal(-1, Time.utc(2000) <=> ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1, 0, 0, 1), TimeZone['UTC'] ))
   end
+  
+  def test_minus_with_time_with_zone
+    assert_equal  86_400.0, Time.utc(2000, 1, 2) - ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1), TimeZone['UTC'] )
+  end
 
   protected
     def with_timezone(new_tz = 'US/Eastern')
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 1a2f3e6e47..9276656db5 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -121,6 +121,16 @@ uses_tzinfo 'TimeWithZoneTest' do
     def test_minus_with_duration
       assert_equal Time.utc(1999, 12, 26, 19, 0 ,0), (@twz - 5.days).time
     end
+    
+    def test_minus_with_time
+      assert_equal  86_400.0,  ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 2), TimeZone['UTC'] ) - Time.utc(2000, 1, 1)
+    end
+    
+    def test_minus_with_time_with_zone
+      twz1 = ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 1), TimeZone['UTC'] )
+      twz2 = ActiveSupport::TimeWithZone.new( Time.utc(2000, 1, 2), TimeZone['UTC'] )
+      assert_equal  86_400.0,  twz2 - twz1
+    end
       
     def test_to_time
       assert_equal @twz, @twz.to_time