Allow exposures to call methods defined in included modules (#307)

* Allow exposures to call methods defined in included modules
* Fix #258

* Update Changelog with the Pull Request link

Author: robertoz-01

CHANGELOG.md

@@ -8,6 +8,7 @@
 #### Fixes
 
 * Your contribution here.
+* [#258](https://github.com/ruby-grape/grape-entity/pull/307): Allow exposures to call methods defined in modules included in an entity [@robertoz-01](https://github.com/robertoz-01).
 
 ### 0.7.1 (2018-01-30)
 

lib/grape_entity/entity.rb

@@ -506,13 +506,20 @@ def value_for(key, options = Options.new)
     end
 
     def delegate_attribute(attribute)
-      if respond_to?(attribute, true) && Grape::Entity > method(attribute).owner
+      if is_defined_in_entity?(attribute)
         send(attribute)
       else
         delegator.delegate(attribute)
       end
     end
 
+    def is_defined_in_entity?(attribute)
+      return false unless respond_to?(attribute, true)
+
+      ancestors = self.class.ancestors
+      ancestors.index(Grape::Entity) > ancestors.index(method(attribute).owner)
+    end
+
     alias as_json serializable_hash
 
     def to_json(options = {})

spec/grape_entity/entity_spec.rb

@@ -1376,6 +1376,18 @@ class TestEntity < Grape::Entity
         expect(res).to have_key :nonexistent_attribute
       end
 
+      it "exposes attributes defined through module inclusion" do
+        module SharedAttributes
+          def a_value
+            3.14
+          end
+        end
+        fresh_class.include(SharedAttributes)
+        fresh_class.expose :a_value
+        res = fresh_class.new(model).serializable_hash
+        expect(res[:a_value]).to eq(3.14)
+      end
+
       it 'does not expose attributes that are generated by a block but have not passed criteria' do
         fresh_class.expose :nonexistent_attribute,
                            proc: ->(_, _) { 'I exist, but it is not yet my time to shine' },