Support for testing OmniAuth strategies.

@example Usage

  class MyStrategyTest < Test::Unit::TestCase
    include OmniAuth::Test::StrategyTestCase
    def strategy
      # return the parameters to a Rack::Builder map call:
      [MyStrategy.new, :some, :configuration, :options => 'here']
    end
    setup do
      post '/auth/my_strategy/callback', :user => { 'name' => 'Dylan', 'id' => '445' }
    end
  end