remove dependent objects on destroy

app/models/db.rb

@@ -2,7 +2,10 @@
 
 # Database object
 class Db < ActiveRecord::Base
-  belongs_to :root_folder, foreign_key: 'db_folder_id', class_name: 'DbFolder'
+  belongs_to :root_folder,
+             foreign_key: 'db_folder_id',
+             class_name: 'DbFolder',
+             dependent: :destroy
   belongs_to :nilm
 
   def url

app/models/db_folder.rb

@@ -4,8 +4,13 @@
 # and one or more DbFolders as subfolders
 class DbFolder < ActiveRecord::Base
   belongs_to :parent, class_name: 'DbFolder'
-  has_many :subfolders, class_name: 'DbFolder', foreign_key: 'parent_id'
-  has_many :db_files
+  has_many :subfolders,
+           class_name: 'DbFolder',
+           foreign_key: 'parent_id',
+           dependent: :destroy
+
+  has_many :db_files,
+           dependent: :destroy
 
   def self.defined_attributes
     [:name, :description, :hidden]

spec/models/db_file_spec.rb

@@ -11,6 +11,14 @@ RSpec.describe 'DbFile' do
     specify { expect(db_file).to respond_to(:hidden) }
   end
 
+  it 'removes streams destroyed' do
+    stream = DbStream.create
+    file = DbFile.create
+    file.db_streams << stream
+    file.destroy
+    expect(DbStream.find_by_id(stream.id)).to be nil
+  end
+
   describe 'remove' do
     let(:db_streams) { FactoryGirl.build_list(:db_stream, 5) }
     let(:db_file) { FactoryGirl.create(:db_file) }
@@ -31,4 +39,5 @@ RSpec.describe 'DbFile' do
       expect(db_service).to have_received(:remove_file)
     end
   end
+
 end

spec/models/db_folder_spec.rb

@@ -12,6 +12,23 @@ RSpec.describe 'DbFolder' do
     specify { expect(db_folder).to respond_to(:hidden) }
   end
 
+  describe 'when destroyed' do
+    before(:all) do
+      @folder = DbFolder.create
+      @subfolder = DbFolder.create
+      @file = DbFile.create
+      @folder.subfolders << @subfolder
+      @folder.db_files << @file
+      @folder.destroy
+    end
+    it 'removes subfolders' do
+      expect(DbFolder.find_by_id(@subfolder.id)).to be_nil
+    end
+    it 'removes subfiles' do
+      expect(DbFile.find_by_id(@file.id)).to be_nil
+    end
+  end
+
   describe 'insert_file' do
     let(:db_folder) { FactoryGirl.create(:db_folder) }
     let(:new_file) { FactoryGirl.create(:db_file) }

spec/models/db_spec.rb

 # frozen_string_literal: true
 require 'rails_helper'
 
-RSpec.describe 'DbStream' do
+RSpec.describe 'Db' do
   describe 'object' do
     let(:db) { Db.new }
     specify { expect(db).to respond_to(:url) }
     specify { expect(db).to respond_to(:root_folder) }
   end
+
+  it 'removes the root folder when destroyed' do
+    root_folder = DbFolder.create
+    db = Db.create(root_folder: root_folder)
+    db.destroy
+    expect(DbFolder.find_by_id(root_folder.id)).to be nil
+  end
 end