module Shoulda::ActionController::Macros

should_set_session(:message) { "Free stuff" }
should_set_session(:user_id) { @user.id }

Example:

that returns the expected value.
session is correct. Expects the session key as a parameter, and a block
Macro that creates a test asserting that a value returned from the

def should_set_session(key, &block)
  matcher = set_session(key)
  should matcher.description do
    expected_value = instance_eval(&block)
    matcher = matcher.to(expected_value)
    assert_accepts matcher, @controller
  end
end