Allow cascade delete Unit/Quantity

Closes #32

app/models/unit.rb

@@ -3,7 +3,8 @@ class Unit < ApplicationRecord
 
   belongs_to :user, optional: true
   belongs_to :base, optional: true, class_name: "Unit"
-  has_many :subunits, class_name: "Unit", inverse_of: :base, dependent: :restrict_with_error
+  has_many :subunits, class_name: "Unit", inverse_of: :base,
+    dependent: :restrict_with_error
 
   validate if: ->{ base.present? } do
     errors.add(:base, :user_mismatch) unless user_id == base.user_id

app/models/user.rb

@@ -12,10 +12,10 @@ class User < ApplicationRecord
     disabled: 0,    # administratively disallowed to sign in
   }, default: :active, validate: true
 
-  has_many :readouts, dependent: :destroy
+  has_many :readouts, dependent: :delete_all
   accepts_nested_attributes_for :readouts
-  has_many :quantities, dependent: :destroy
+  has_many :quantities, dependent: :delete_all
-  has_many :units, dependent: :destroy
+  has_many :units, dependent: :delete_all
 
   validates :email, presence: true, uniqueness: true,
     length: {maximum: type_for_attribute(:email).limit}

db/migrate/20230602185352_create_units.rb

@@ -5,7 +5,7 @@ class CreateUnits < ActiveRecord::Migration[7.0]
       t.string :symbol, null: false, limit: 15
       t.text :description
       t.decimal :multiplier, null: false, precision: 30, scale: 15, default: 1.0
-      t.references :base, foreign_key: {to_table: :units}
+      t.references :base, foreign_key: {to_table: :units, on_delete: :cascade}
 
       t.timestamps null: false
     end

db/migrate/20250104194343_create_quantities.rb

@@ -4,7 +4,7 @@ class CreateQuantities < ActiveRecord::Migration[7.2]
       t.references :user, foreign_key: true
       t.string :name, null: false, limit: 31
       t.text :description
-      t.references :parent, foreign_key: {to_table: :quantities}
+      t.references :parent, foreign_key: {to_table: :quantities, on_delete: :cascade}
 
       t.timestamps null: false
 

db/schema.rb

@@ -69,11 +69,11 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
-  add_foreign_key "quantities", "quantities", column: "parent_id"
+  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
   add_foreign_key "quantities", "users"
   add_foreign_key "readouts", "quantities"
   add_foreign_key "readouts", "units"
   add_foreign_key "readouts", "users"
-  add_foreign_key "units", "units", column: "base_id"
+  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
   add_foreign_key "units", "users"
 end

db/seeds/templates/units.erb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
   units = {}
 <% Unit.defaults.ordered.each do |unit| %>
 <%= "\n" if unit.base.nil? %>

db/seeds/units.rb

@@ -1,5 +1,5 @@
 Unit.transaction do
-  Unit.defaults.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+  Unit.defaults.delete_all
 
   units = {}
 

test/system/units_test.rb

@@ -6,14 +6,14 @@ require "application_system_test_case"
 #  * user with no units
 
 class UnitsTest < ApplicationSystemTestCase
-  LINK_LABELS = {
+  LINK_LABELS = {}
-    new_unit: t('units.index.new_unit'),
-    new_subunit: t('units.unit.new_subunit'),
-    edit: nil
-  }
 
   setup do
     @user = sign_in
+
+    LINK_LABELS.clear
+    LINK_LABELS[:new_unit] = t('units.index.new_unit')
+    LINK_LABELS[:new_subunit] = t('units.unit.new_subunit')
     LINK_LABELS[:edit] = Regexp.union(@user.units.map(&:symbol))
 
     visit units_path
@@ -26,7 +26,7 @@ class UnitsTest < ApplicationSystemTestCase
     end
 
     # Cannot #destroy_all due to {dependent: :restrict*} on Unit.subunits association
-    @user.units.order(Unit.arel_table[:base_id].eq(nil)).delete_all
+    @user.units.delete_all
     visit units_path
     within 'tbody' do
       assert_selector 'tr', count: 1

test/system/users_test.rb

@@ -157,9 +157,10 @@ class UsersTest < ApplicationSystemTestCase
     end
     assert_difference ->{ User.count }, -1 do
       accept_confirm { click_on t("users.registrations.edit.delete") }
-    end
       assert_current_path new_user_session_path
     end
+    assert_text t("devise.registrations.destroyed")
+  end
 
   test "index forbidden for non admin" do
     sign_in user: users.reject(&:admin?).select(&:confirmed?).sample