Using Object#tap to create scopes

braintree.rb

Braintree::Configuration.tap do |config|
  if settings = YAML.load_file(Rails.root.join('config', 'braintree.yml'))[Rails.env]
    config.environment  = :sandbox
    config.merchant_id  = settings['merchant_id']
    config.public_key   = settings['public_key']
    config.private_key  = settings['private_key']
  end
end

template.html.erb

<div class="ninja>
  <div>Name: <%= @ninja.name %></div>
  <% @ninja.victims.last.tap do |victim| %>
    <div>Last victim: <%= victim.name %></div>
    <div>Date killed: <%= victim.killed_at %></div>
  <% end %>
</div>

testing.rb

test 'has_weapon_skill' do
  build(:bad_ass, name: 'Chuck Norris').tap do |bad_ass|
    assert bad_ass.has_weapon_skill?('uzi')
    assert !bad_ass.has_weapon_skill?('nunchucks')
  end

  build(:bad_ass, name: 'Bruce Lee').tap do |bad_ass|
    assert !bad_ass.has_weapon_skill?('uzi')
    assert bad_ass.has_weapon_skill?('nunchucks')
  end
end