export_active_orders_spec.rb

# Poor specs
# ==========

# 3rd party library and framework methods are used directly to facilitate tests
describe ExportActiveOrders do
  describe '.call' do
    it 'exports all active orders and returns a path to exported file' do
      create_list(:order, 2, :active)
      create(:order, :inactive)

      path = ExportActiveOrders.call

      expected_columns = Order.where(active: true).pluck(:customer_name, :total_value)
      book = Spreadsheet.open(path)
      sheet = book.worksheet(0)
      expect(sheet.rows).to match_array(expected_columns)
    end
  end
end

# Good specs
# ============

# 3rd party library usage is abstracted away to helper. Instead of using framework methods
# to retrieve expected values, those values are provided explicitly.
module Support
  module XlsHelpers
    def open_spreadsheet(path)
      book = Spreadsheet.open(path)
      sheet = book.worksheet(0)
      sheet.rows
    end
  end
end

RSpec.configure do |config|
  config.include Support::XlsHelpers
end

describe ExportActiveOrders do
  describe '.call' do
    it 'exports all active orders and returns a path to exported file' do
      create(:order, :active, customer_name: 'Bruce Wayne', total_value: 1000)
      create(:order, :inactive, customer_name: 'Dr. Strange', total_value: 1200)
      create(:order, :active, customer_name: 'Edward Nygma', total_value: 500)

      path = ExportActiveOrders.call

      rows = open_spreadsheet(path)
      expect(rows).to match_array([['Bruce Wayne', 1000],['Edward Nygma', 500]])
    end
  end
end