Create valuation comments creation ability

Why:

Only admins or valuators (for those investments they've assigned) can
create internal valuation comments on them.

How:

* Creating a new `comment_valuation` ability for admins and valuators in
the same manner the `valuate` ability works.

* Adding a validation at Comment model for those with `valuation` flag
active that checks if the author can make a valuation comment on the
commentable, as well as the respective active record error messages.
This will prevent comments from being created at a controller level as
well.

* Improving comment factory trait `valuation` to have an associated
investment, author that is a valuator and setting the valuator on the
valuators list of the investment

app/models/abilities/administrator.rb

@@ -55,7 +55,7 @@ def initialize(user)
       can [:read, :create, :update, :destroy], Budget::Group
       can [:read, :create, :update, :destroy], Budget::Heading
       can [:hide, :update, :toggle_selection], Budget::Investment
-      can :valuate, Budget::Investment
+      can [:valuate, :comment_valuation], Budget::Investment
       can :create, Budget::ValuatorAssignment
 
       can [:search, :edit, :update, :create, :index, :destroy], Banner

app/models/abilities/valuator.rb

@@ -5,8 +5,8 @@ class Valuator
     def initialize(user)
       valuator = user.valuator
       can [:read, :update, :valuate], SpendingProposal
-      can [:read, :update, :valuate], Budget::Investment, id: valuator.investment_ids
-      cannot [:update, :valuate], Budget::Investment, budget: { phase: 'finished' }
+      can [:read, :update, :valuate, :comment_valuation], Budget::Investment, id: valuator.investment_ids
+      cannot [:update, :valuate, :comment_valuation], Budget::Investment, budget: { phase: 'finished' }
     end
   end
 end

app/models/comment.rb

@@ -20,6 +20,7 @@ class Comment < ActiveRecord::Base
   validates :commentable_type, inclusion: { in: COMMENTABLE_TYPES }
 
   validate :validate_body_length
+  validate :comment_valuation, if: -> { valuation }
 
   belongs_to :commentable, -> { with_hidden }, polymorphic: true, counter_cache: true
   belongs_to :user, -> { with_hidden }
@@ -133,4 +134,9 @@ def validate_body_length
       validator.validate(self)
     end
 
+    def comment_valuation
+      unless author.can?(:comment_valuation, commentable)
+        errors.add(:valuation, :cannot_comment_valuation)
+      end
+    end
 end

config/locales/en/activerecord.yml

@@ -296,6 +296,10 @@ en:
             image:
               image_width: "Width must be %{required_width}px"
               image_height: "Height must be %{required_height}px"
+        comment:
+          attributes:
+            valuation:
+              cannot_comment_valuation: 'You cannot comment a valuation'
       messages:
         record_invalid: "Validation failed: %{errors}"
         restrict_dependent_destroy:

config/locales/es/activerecord.yml

@@ -292,6 +292,10 @@ es:
             image:
               image_width: "Debe tener %{required_width}px de ancho"
               image_height: "Debe tener %{required_height}px de alto"
+        comment:
+          attributes:
+            valuation:
+              cannot_comment_valuation: 'No puedes comentar una evaluación'
       messages:
         record_invalid: 'Error de validación: %{errors}'
         restrict_dependent_destroy:

spec/factories.rb

@@ -468,6 +468,12 @@
 
     trait :valuation do
       valuation true
+      association :commentable, factory: :budget_investment
+      before :create do |valuation|
+        valuator = create(:valuator)
+        valuation.author = valuator.user
+        valuation.commentable.valuators << valuator
+      end
     end
   end