give me my assert_response back!

Did you just upgrade Ruby on Rails and now all of your assert_response() tests are failing? Simply add the following code to test/test_helper.rb and everything will work again!

ActionDispatch::Assertions::ResponseAssertions.instance_eval do
  # Override so deprecation warnings stop popping up. This uses a proper
  # +assert+ method but retains the functionality of +assert_response+.
  define_method(:assert_response_test) do |expected_status|
    response_status = response.send :status
    assert_equal response_status, expected_status, \
      "Expected response to be <#{expected_status}>, but was <#{response_status}>"
  end
end

Major shout-outs to Rob Di Marco who actually wrote this and figured out that instance_eval was the proper method to use here, not class_eval... :D

update!

We have drastically improved this little snippet and ripped a monkey patch directly from Rails 4. Here's the full code, pasted here in case you want to read it: