Allow sections to be unique within lessons only

- Add migration to fix the unique index
- Add scope to the uniqueness validation
- Add user factory
- Add user association to lesson factory
- Lesson factory corrections
- Add section factory
- Add section model spec

NOTE: We modify the start_time and end_time validations to provide a
default value for lesson.duration_in_seconds because there's an issue
with shoulda matchers and validations that refer to associated models
according to this issue thoughtbot/shoulda-matchers#1435

app/models/section.rb

@@ -8,7 +8,8 @@ class Section < ApplicationRecord
     class_name: "VideoPoint",
     mapping: [ %w(end_time_hour hour), %w(end_time_minute minute), %w(end_time_second second) ]
 
-  validates :name, presence: true
+  validates :name, presence: true, uniqueness: { scope: :lesson_id }
+
   validates :start_time_hour, :start_time_minute, :start_time_second,
     presence: true,
     numericality: {
@@ -29,16 +30,21 @@ class Section < ApplicationRecord
       less_than_or_equal_to: 59
     }
 
+  # Due to this issue in shoulda matchers library we'll have to add a default max value
+  # https://github.com/thoughtbot/shoulda-matchers/issues/1435
   validates :start_time,
     numericality: {
-      less_than:  -> (section) { section.lesson.duration_in_seconds },
-      message: -> (object, data) { "must be less than #{object.lesson.duration_in_seconds}" }
+      less_than:  -> (section) { section.lesson&.duration_in_seconds || 9999.0 },
+      message: -> (object, data) { "must be less than #{object.lesson.duration_in_seconds}" },
+      allow_nil: true
     }
 
+  # Due to this issue in shoulda matchers library we'll have to add a default max value
+  # https://github.com/thoughtbot/shoulda-matchers/issues/1435
   validates :end_time,
     numericality: {
-      less_than_or_equal_to: -> (section) { section.lesson.duration_in_seconds },
-      message: -> (object, data) { "must be less than #{object.lesson.duration_in_seconds}" }
+      less_than_or_equal_to: -> (section) { section.lesson&.duration_in_seconds || 9999.0 },
+      message: -> (object, data) { "must be less than #{object.lesson.duration_in_seconds}" },
     }
 
   validates :end_time,

db/migrate/20240723030225_fix_section_name_uniqueness_index.rb

@@ -0,0 +1,6 @@
+class FixSectionNameUniquenessIndex < ActiveRecord::Migration[7.0]
+  def change
+    remove_index :sections, :name
+    add_index :sections, [:name, :lesson_id], unique: true
+  end
+end

spec/factories/lesson.rb

@@ -3,10 +3,11 @@
     name do
       "#{Faker::Music::RockBand.song} - #{Faker::Music::RockBand.name}"
     end
-    video_url { Faker::Internel.url(host: 'youtu.be') }
+    video_url { Faker::Internet.url(host: "youtu.be", scheme: "https") }
     duration_in_seconds do
-      Faker::Number.between(from: 0.0, to: 5.minutes.seconds.to_f)
+      Faker::Number.between(from: 0, to: 5.minutes.seconds)
     end
     instrument
+    user
   end
 end

spec/factories/section.rb

@@ -0,0 +1,16 @@
+FactoryBot.define do
+  factory :section do
+    lesson
+    sequence(:name) { |n| "Section #{n}" }
+
+    start_time_hour { 0 }
+    start_time_minute { 0 }
+    start_time_second { 1 }
+
+    end_time_hour { 0 }
+    end_time_minute { 0 }
+    end_time_second { Faker::Number.between(from: 1, to: 59 ) }
+
+    playback_speed { 0.5.step(by: 0.5, to: 2.0).to_a.sample }
+  end
+end

spec/factories/user.rb

@@ -0,0 +1,7 @@
+FactoryBot.define do
+  factory :user do
+    sequence(:email) { |n| "user#{n}@example.com" }
+    password { "password123" }
+    confirmed_at { Date.yesterday }
+  end
+end

spec/models/section_spec.rb

@@ -0,0 +1,13 @@
+require 'rails_helper'
+
+describe Section, type: :model do
+  subject { create(:section) }
+
+  describe 'associations' do
+    it { should belong_to(:lesson) }
+  end
+
+  describe 'validations' do
+    it { should validate_uniqueness_of(:name).scoped_to(:lesson_id) }
+  end
+end