refactor more logic into AuxTableConfig

spec/active_record/aux_table_spec.rb

@@ -28,8 +28,14 @@ RSpec.describe HasAuxTable do
   before(:all) do
     # Set up the database schema for testing
     ActiveRecord::Schema.define do
+      create_table :vehicle_lots do |t|
+        t.string :name
+        t.timestamps
+      end
+
       create_base_table :vehicles do |t|
         t.string :name
+        t.references :vehicle_lot, foreign_key: { to_table: :vehicle_lots }
         t.timestamps
 
         t.create_aux :car do |t|
@@ -92,6 +98,11 @@ RSpec.describe HasAuxTable do
 
     class Vehicle < ActiveRecord::Base
       include HasAuxTable
+      belongs_to :vehicle_lot
+    end
+
+    class VehicleLot < ActiveRecord::Base
+      has_many :vehicles
     end
 
     class Car < Vehicle
@@ -191,16 +202,40 @@ RSpec.describe HasAuxTable do
     car =
       Car.create!(name: "Honda Civic", fuel_type: "gasoline", engine_size: 2.0)
     expect(car.attributes).to match(
-      "type" => "Car",
-      "id" => car.id,
-      "name" => "Honda Civic",
-      "fuel_type" => "gasoline",
-      "engine_size" => be_within(0.001).of(2.0),
-      "created_at" => be_within(0.001).of(car.created_at),
-      "updated_at" => be_within(0.001).of(car.updated_at)
+      hash_including(
+        "type" => "Car",
+        "id" => car.id,
+        "name" => "Honda Civic",
+        "fuel_type" => "gasoline",
+        "engine_size" => be_within(0.001).of(2.0),
+        "created_at" => be_within(0.001).of(car.created_at),
+        "updated_at" => be_within(0.001).of(car.updated_at)
+      )
     )
   end
 
+  it "can be created as the base class" do
+    vehicle = Vehicle.create(type: "Vehicle", name: "big tractor")
+    expect(vehicle.attributes).to match(
+      hash_including(
+        "type" => "Vehicle",
+        "id" => vehicle.id,
+        "name" => "big tractor",
+        "created_at" => be_within(0.001).of(vehicle.created_at),
+        "updated_at" => be_within(0.001).of(vehicle.updated_at)
+      )
+    )
+  end
+
+  it "can be created through an association" do
+    lot = VehicleLot.create(name: "lot1")
+    lot.vehicles.create { |b| b.name = "vehicle1" }
+    lot.save!
+    lot.reload
+    expect(lot.vehicles.count).to eq(1)
+    expect(lot.vehicles.first.name).to eq("vehicle1")
+  end
+
   describe "database integration" do
     it "provides automatic attribute accessors for auxiliary table columns" do
       vehicle = Car.create!(name: "Honda Civic")