fix domain tests

Gemfile

@@ -73,6 +73,7 @@ group :test, :development do
   gem 'rspec-rails', '~> 3.1.0'
   gem 'rspec-its', '~> 1.1.0'
   gem 'rspec-collection_matchers', '~> 1.1.2'
+  gem 'rspec-mocks', '~> 3.1.3'
 end
 
 group :test do

Gemfile.lock

@@ -365,6 +365,7 @@ DEPENDENCIES
   rails_config (~> 0.4.2)
   rspec-collection_matchers (~> 1.1.2)
   rspec-its (~> 1.1.0)
+  rspec-mocks (~> 3.1.3)
   rspec-rails (~> 3.1.0)
   sass-rails (~> 4.0.4)
   seedbank (~> 0.3.0)

app/models/domain/tree_structure.rb

@@ -12,7 +12,7 @@ class Domain < ActiveRecord::Base
   after_save :sync_children
   
   # this goes after sync_parent, to order callbacks correctly 
-  acts_as_nested_interval virtual_root: true, dependent: :nullify
+  acts_as_nested_interval virtual_root: true, dependent: :restrict_with_error
   
   validate :domain_ownership
   def domain_ownership

spec/models/domain_spec.rb

@@ -67,7 +67,7 @@ describe Domain do
 
     User.do_as(user) do
       # stub a parent domain on another user account, with no permissions present
-      mock_domain = mock(
+      mock_domain = double(
         :user_id => user3.id, 
         :user => user3, 
         :name => 'x',