module ActionDispatch::Assertions::ResponseAssertions

assert_response 401
# Asserts that the response code was status code 401 (unauthorized)

assert_response :redirect
# Asserts that the response was a redirection

See Rack::Utils::SYMBOL_TO_STATUS_CODE for a full list.
or its symbolic equivalent assert_response(:not_implemented).
You can also pass an explicit status number like assert_response(501)

* :error - Status code was in the 500-599 range
* :missing - Status code was 404
* :redirect - Status code was in the 300-399 range
* :success - Status code was in the 200-299 range

Asserts that the response is one of the following types:

def assert_response(type, message = nil)
  message ||= generate_response_message(type)
  if RESPONSE_PREDICATES.keys.include?(type)
    assert @response.send(RESPONSE_PREDICATES[type]), message
  else
    assert_equal AssertionResponse.new(type).code, @response.response_code, message
  end
end