Playground for RSpec/Rails/ActiveRecord blah blah foo

Gemfile

# frozen_string_literal: true
source "https://rubygems.org"

gem "rails"
gem "rspec"
gem "sqlite3"

scratch.rb

require 'rails'
require 'active_record'
require 'rspec'
require 'sqlite3'
require 'fileutils'

FileUtils.rm("users.db")

ActiveRecord::Base.establish_connection(
  adapter: 'sqlite3',
  database: './users.db'
)

ActiveRecord::Schema.define do
  create_table :widgets do |t|
    t.string :name
    t.timestamps
  end
end

class Widget < ActiveRecord::Base
end

def last_modified(scopes, non_scopes=nil)
  [ 
    scopes.map do |scope|
      scope.maximum(:updated_at)
    end, 
    non_scopes 
  ].flatten.compact.max
end

require 'rspec/autorun'

describe '#last_modified' do
  before do
    Widget.create!(name: 'foo')
    Widget.create!(name: 'af')
    @expected = Widget.create!(name: 'noo')
  end

  it 'returns the max number for class Widget' do
    @expected.touch
    expect(last_modified([Widget])).to eq(@expected.updated_at)
  end

  it 'returns the greater of the scopes or non_scopes' do
    ts = Time.now
    expect(last_modified([Widget], ts)).to eq(ts)
  end

  it 'returns the scope if scope has the greater value' do
    expect(last_modified([Widget], 10.weeks.ago)).to eq(@expected.updated_at)
  end
end

I had to swap to FileUtils.rm("users.db", force: true), but then it worked. Thanks for sharing!