Casted array should notify changes on deletion

Otherwise there is no direct way to delete particular elements.

Workaround with assigning to another array without those elements
is pretty ugly.

* Should notify on deletion at a particular index (Array#delete_at)
* Should notify on deletion of a particular element (Array#delete)

Signed-off-by: Marcos Tapajós <tapajos@gmail.com>

lib/couchrest/model/casted_array.rb

@@ -50,6 +50,16 @@ module CouchRest::Model
       super
     end
 
+    def delete(obj)
+      couchrest_parent_will_change! if use_dirty? && self.length > 0
+      super(obj)
+    end
+
+    def delete_at(index)
+      couchrest_parent_will_change! if use_dirty? && self.length > 0
+      super(index)
+    end
+
     def build(*args)
       obj = casted_by_property.build(*args)
       self.push(obj)

spec/couchrest/dirty_spec.rb

@@ -257,6 +257,50 @@ describe "Dirty" do
       end
     end
 
+    it "should report changes on deletion from an array" do
+      should_change_array do |array, obj|
+        array << "keyword"
+        obj.save!
+        array.delete_at(0)
+      end
+
+      should_change_array do |array, obj|
+        array << "keyword"
+        obj.save!
+        array.delete("keyword")
+      end
+    end
+
+    it "should report changes on deletion from an array after reload" do
+      should_change_array do |array, obj|
+        array << "keyword"
+        obj.save!
+        obj.reload
+        array.delete_at(0)
+      end
+
+      should_change_array do |array, obj|
+        array << "keyword"
+        obj.save!
+        obj.reload
+        array.delete("keyword")
+      end
+    end
+
+    it "should report no changes on deletion from an empty array" do
+      should_not_change_array do |array, obj|
+        array.clear
+        obj.save!
+        array.delete_at(0)
+      end
+
+      should_not_change_array do |array, obj|
+        array.clear
+        obj.save!
+        array.delete("keyword")
+      end
+    end
+
     it "should report changes if an array is pushed" do
       should_change_array do |array, obj|
         array.push("keyword")