Populate root account id for favorites

Test plan:
-specs should pass
-create a favorite
-inspect in rails console 
-verify root account id is set 

Fixes VICE-343

flag=none

Change-Id: Ib13b7db057bfe1fd7a1d78b30a5ed3a30ae85799
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/239853
Tested-by: Service Cloud Jenkins <[email protected]>
Reviewed-by: Ben Nelson <[email protected]>
QA-Review: Caleb Guanzon <[email protected]>
Product-Review: Caleb Guanzon <[email protected]>

app/models/account.rb

@@ -31,6 +31,7 @@ class Account < ActiveRecord::Base
   belongs_to :root_account, :class_name => 'Account'
 
   has_many :courses
+  has_many :favorites, inverse_of: :root_account
   has_many :all_courses, :class_name => 'Course', :foreign_key => 'root_account_id'
   has_one :terms_of_service, :dependent => :destroy
   has_one :terms_of_service_content, :dependent => :destroy

app/models/favorite.rb

@@ -18,12 +18,18 @@
 class Favorite < ActiveRecord::Base
   belongs_to :context, polymorphic: [:course, :group]
   belongs_to :user
+  belongs_to :root_account, class_name: "Account", inverse_of: :favorites
   validates_inclusion_of :context_type, :allow_nil => true, :in => ['Course', 'Group'].freeze
   scope :by, lambda { |type| where(:context_type => type) }
 
+  before_create :populate_root_account_id
   after_save :touch_user
 
   def touch_user
     self.class.connection.after_transaction_commit { user.touch }
   end
+
+  def populate_root_account_id
+    self.root_account = self.context.root_account
+  end
 end

spec/models/favorite_spec.rb

@@ -0,0 +1,26 @@
+#
+# Copyright (C) 2020 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+
+require 'spec_helper'
+
+describe Favorite do
+  it 'should populate root account' do
+    student_in_course()
+    favorite = @user.favorites.create!(context: @course)
+    expect(favorite.root_account).to eq @course.root_account
+  end
+end