GuestDevice#parent_device

To be honest, I only added this to make rubocop happy.
But it did feel like it was missing and made the specs a little prettier.

app/models/guest_device.rb

@@ -9,12 +9,13 @@ class GuestDevice < ApplicationRecord
 
   belongs_to :switch    # pNICs link to one switch
   belongs_to :lan       # vNICs link to one lan
+  belongs_to :parent_device, :class_name => "GuestDevice"
 
   has_one :network, :foreign_key => "device_id", :dependent => :destroy, :inverse_of => :guest_device
   has_many :miq_scsi_targets, :dependent => :destroy
 
   has_many :firmwares, :dependent => :destroy
-  has_many :child_devices, :foreign_key => "parent_device_id", :class_name => "GuestDevice", :dependent => :destroy
+  has_many :child_devices, :foreign_key => "parent_device_id", :class_name => "GuestDevice", :dependent => :destroy, :inverse_of => :parent_device
 
   has_many :physical_network_ports, :dependent => :destroy
   has_many :connected_physical_switches, :through => :physical_network_ports

spec/models/guest_device_spec.rb

@@ -35,8 +35,8 @@
   describe "#child_device" do
     it "brings back children" do
       parent = FactoryBot.create(:guest_device)
-      child1 = FactoryBot.create(:guest_device, :parent_device_id => parent.id)
-      child2 = FactoryBot.create(:guest_device, :parent_device_id => parent.id)
+      child1 = FactoryBot.create(:guest_device, :parent_device => parent)
+      child2 = FactoryBot.create(:guest_device, :parent_device => parent)
       FactoryBot.create(:guest_device) # sad path (though the let! probably created lots of those)
 
       expect(parent.reload.child_devices).to match_array([child1, child2])