Cover all mongo array update operators with tests. Include $pull and …

…$pop in special handling conditions for Mongoize

lib/mongoid/atomic_update_preparer.rb

@@ -49,7 +49,7 @@ def prepare_operation(klass, key, value)
 
       # Get the value for the provided operator, klass, key and value.
       #
-      # This is necessary for special cases like $rename, $addToSet and $push.
+      # This is necessary for special cases like $rename, $addToSet, $push, $pull and $pop.
       #
       # @param [ String ] operator The operator.
       # @param [ Class ] klass The model class.
@@ -60,7 +60,7 @@ def prepare_operation(klass, key, value)
       def value_for(operator, klass, key, value)
         case operator
         when '$rename' then value.to_s
-        when '$addToSet', '$push' then value.mongoize
+        when '$addToSet', '$push', '$pull', '$pop' then value.mongoize
         else mongoize_for(operator, klass, key, value)
         end
       end

spec/mongoid/contextual/mongo_spec.rb

@@ -3640,6 +3640,75 @@
               expect(new_order.reload.genres).to eq(["electronic"])
             end
           end
+
+          context "when operation is $pull" do
+            context "when pulling single element" do
+
+              before do
+                depeche_mode.update_attribute(:genres, ["electronic", "pop"])
+                new_order.update_attribute(:genres, ["electronic", "pop"])
+                context.update_all("$pull" => { genres: "electronic" })
+              end
+
+              it "updates the first matching document" do
+                expect(depeche_mode.reload.genres).to eq(["pop"])
+              end
+
+              it "updates the last matching document" do
+                expect(new_order.reload.genres).to eq(["pop"])
+              end
+            end
+
+            context "when pulling based on condition" do
+              before do
+                depeche_mode.update_attribute(:genres, ["electronic", "pop", "dance"])
+                new_order.update_attribute(:genres, ["electronic", "pop", "dance"])
+                context.update_all("$pull" => { genres: {'$in' => ["electronic", "pop"] }})
+              end
+
+              it "updates the first matching document" do
+                expect(depeche_mode.reload.genres).to eq(["dance"])
+              end
+
+              it "updates the last matching document" do
+                expect(new_order.reload.genres).to eq(["dance"])
+              end
+            end
+          end
+
+          context "when operation is $pop" do
+
+            before do
+              depeche_mode.update_attribute(:genres, ["pop", "electronic" ])
+            end
+
+            it "removes first element in array" do
+              context.update_all("$pop" => { genres: -1 })
+              expect(depeche_mode.reload.genres).to eq(["electronic"])
+            end
+
+            it "removes last element in array" do
+              context.update_all("$pop" => { genres: 1 })
+              expect(depeche_mode.reload.genres).to eq(["pop"])
+            end
+          end
+
+          context "when operation is $pullAll" do
+
+            before do
+              depeche_mode.update_attribute(:genres, ["pop", "electronic", "dance" ])
+              new_order.update_attribute(:genres, ["electronic", "pop", "dance"])
+              context.update_all("$pullAll" => { genres: ["pop", "electronic"] })
+            end
+
+            it "updates the first matching document" do
+              expect(depeche_mode.reload.genres).to eq(["dance"])
+            end
+
+            it "updates the last matching document" do
+              expect(new_order.reload.genres).to eq(["dance"])
+            end
+          end
         end
 
         context 'when using aliased field names' do