Restore versions DB table and add learning tests

db/migrate/20190302091059_restore_versions.rb

@@ -0,0 +1,15 @@
+class RestoreVersions < ActiveRecord::Migration
+  def change
+    drop_table :versions
+
+    create_table :versions do |t|
+      t.string :item_type, :null => false
+      t.integer :item_id, :null => false
+      t.string :event, :null => false
+      t.string :whodunnit
+      t.text :object
+      t.datetime :created_at
+    end
+    add_index :versions, [:item_type, :item_id]
+  end
+end

db/migrate/20190302111152_add_object_changes_to_versions.rb

@@ -0,0 +1,5 @@
+class AddObjectChangesToVersions < ActiveRecord::Migration
+  def change
+    add_column :versions, :object_changes, :jsonb
+  end
+end

db/structure.sql

@@ -2363,7 +2363,13 @@ ALTER SEQUENCE public.users_id_seq OWNED BY public.users.id;
 
 CREATE TABLE public.versions (
     id integer NOT NULL,
-    depricated_table_but_somehow_paper_trail_tests_fails_without_it text
+    item_type character varying NOT NULL,
+    item_id integer NOT NULL,
+    event character varying NOT NULL,
+    whodunnit character varying,
+    object text,
+    created_at timestamp without time zone,
+    object_changes jsonb
 );
 
 
@@ -3980,6 +3986,13 @@ CREATE INDEX index_users_on_identity_code ON public.users USING btree (identity_
 CREATE INDEX index_users_on_registrar_id ON public.users USING btree (registrar_id);
 
 
+--
+-- Name: index_versions_on_item_type_and_item_id; Type: INDEX; Schema: public; Owner: -; Tablespace: 
+--
+
+CREATE INDEX index_versions_on_item_type_and_item_id ON public.versions USING btree (item_type, item_id);
+
+
 --
 -- Name: index_whois_records_on_domain_id; Type: INDEX; Schema: public; Owner: -; Tablespace: 
 --
@@ -4927,6 +4940,10 @@ INSERT INTO schema_migrations (version) VALUES ('20190102144032');
 
 INSERT INTO schema_migrations (version) VALUES ('20190209150026');
 
+INSERT INTO schema_migrations (version) VALUES ('20190302091059');
+
+INSERT INTO schema_migrations (version) VALUES ('20190302111152');
+
 INSERT INTO schema_migrations (version) VALUES ('20190311111718');
 
 INSERT INTO schema_migrations (version) VALUES ('20190312211614');

lib/gem_ext/paper_trail.rb

@@ -1,10 +1,3 @@
-# the following line is required for PaperTrail >= 4.0.0 with Rails
-PaperTrail::Rails::Engine.eager_load!
-
-PaperTrail::Version.module_eval do
-  self.abstract_class = true
-end
-
 # Store console and rake changes in versions
 if defined?(::Rails::Console)
   PaperTrail.whodunnit = "console-#{`whoami`.strip}"

test/learning/paper_trail_test.rb

@@ -0,0 +1,46 @@
+require 'test_helper'
+
+class Post < ActiveRecord::Base
+  has_paper_trail
+end
+
+class PaperTrailLearningTest < ActiveSupport::TestCase
+  setup do
+    ActiveRecord::Base.connection.create_table :posts do |t|
+      t.string :title
+
+      # Otherwise `touch_with_version` fails silently
+      t.datetime :updated_at
+    end
+  end
+
+  def test_returns_version_list
+    @record = Post.create!(title: 'any')
+
+    assert_equal 1, @record.versions.count
+    assert_respond_to @record.versions.first, :item_id
+  end
+
+  def test_creates_new_version_upon_update
+    @record = Post.create!(title: 'old title')
+    original_record = @record.clone
+
+    assert_difference -> { @record.versions.size } do
+      @record.update!(title: 'new title')
+    end
+    version = @record.versions.last
+    assert_equal @record.id, version.item_id
+    assert_equal @record.class.name, version.item_type
+    assert_equal version.reify, original_record
+    assert_equal ['old title', 'new title'], version.object_changes['title']
+    assert_equal 'update', version.event
+  end
+
+  def test_touch_with_version
+    @record = Post.create!(title: 'any')
+    
+    assert_difference -> { @record.versions.size } do
+      @record.touch_with_version
+    end
+  end
+end