Adds support for setup and teardown callbacks. These callbacks serve as a replacement to overwriting the #setup and #teardown methods of your TestCase.

class ExampleTest < ActiveSupport::TestCase
  setup do
    # ...
  end

  teardown do
    # ...
  end
end
Namespace
Methods
P
Included Modules
Class Public methods
prepended(klass)

Source: show | on GitHub 

# File activesupport/lib/active_support/testing/setup_and_teardown.rb, line 21
def self.prepended(klass)
  klass.include ActiveSupport::Callbacks
  klass.define_callbacks :setup, :teardown
  klass.extend ClassMethods
end