module ActionDispatch::Assertions::RoutingAssertions

assert_routing({ method: 'put', path: '/product/321' }, { controller: "product", action: "update", id: "321" })
# Tests a route with an HTTP method

assert_routing 'controller/action/9', {id: "9", item: "square"}, {controller: "controller", action: "action"}, {}, {item: "square"}
# Tests a route, providing a defaults hash

assert_routing '/store', { controller: 'store', action: 'index' }, {}, {}, 'Route for store index not generated properly'
# Asserts a basic route (controller + default action), with an error message if it fails

assert_routing '/entries/show/23', controller: 'entries', action: 'show', id: 23
# Test a route generated with a specific controller, action, and parameter (id)

assert_routing '/home', controller: 'home', action: 'index'
# Asserts a basic route: a controller with the default action (index)

+message+ parameter allows you to specify a custom error message to display upon failure.
The +extras+ hash allows you to specify options that would normally be provided as a query string to the action. The

and +assert_generates+ into one step.
options and then that options generates path. This essentially combines +assert_recognizes+
Asserts that path and options match both ways; in other words, it verifies that path generates

def assert_routing(path, options, defaults = {}, extras = {}, message = nil)
  assert_recognizes(options, path, extras, message)
  controller, default_controller = options[:controller], defaults[:controller]
  if controller && controller.include?(?/) && default_controller && default_controller.include?(?/)
    options[:controller] = "/#{controller}"
  end
  generate_options = options.dup.delete_if { |k, _| defaults.key?(k) }
  assert_generates(path.is_a?(Hash) ? path[:path] : path, generate_options, defaults, extras, message)
end