# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 85
def assert_generates(expected_path, options, defaults = {}, extras = {}, message = nil)
  if %r{://}.match?(expected_path)
    fail_on(URI::InvalidURIError, message) do
      uri = URI.parse(expected_path)
      expected_path = uri.path.to_s.empty? ? "/" : uri.path
    end
  else
    expected_path = "/#{expected_path}" unless expected_path.start_with?("/")
  end

  options = options.clone
  generated_path, query_string_keys = @routes.generate_extras(options, defaults)
  found_extras = options.reject { |k, _| ! query_string_keys.include? k }

  msg = message || sprintf("found extras <%s>, not <%s>", found_extras, extras)
  assert_equal(extras, found_extras, msg)

  msg = message || sprintf("The generated path <%s> did not match <%s>", generated_path,
      expected_path)
  assert_equal(expected_path, generated_path, msg)
end

Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.

The defaults parameter is unused.

# Asserts that the default action is generated for a route with no action
assert_generates "/items", controller: "items", action: "index"

# Tests that the list action is properly routed
assert_generates "/items/list", controller: "items", action: "list"

# Tests the generation of a route with a parameter
assert_generates "/items/list/1", { controller: "items", action: "list", id: "1" }

# Asserts that the generated route gives us our custom route
assert_generates "changesets/12", { controller: 'scm', action: 'show_diff', revision: "12" }

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 47
def assert_recognizes(expected_options, path, extras = {}, msg = nil)
  if path.is_a?(Hash) && path[:method].to_s == "all"
    [:get, :post, :put, :delete].each do |method|
      assert_recognizes(expected_options, path.merge(method: method), extras, msg)
    end
  else
    request = recognized_request_for(path, extras, msg)

    expected_options = expected_options.clone

    expected_options.stringify_keys!

    msg = message(msg, "") {
      sprintf("The recognized options <%s> did not match <%s>, difference:",
              request.path_parameters, expected_options)
    }

    assert_equal(expected_options, request.path_parameters, msg)
  end
end

Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.

Pass a hash in the second argument (path) to specify the request method. This is useful for routes requiring a specific HTTP method. The hash should contain a :path with the incoming request path and a :method containing the required HTTP verb.

# Asserts that POSTing to /items will call the create action on ItemsController
assert_recognizes({controller: 'items', action: 'create'}, {path: 'items', method: :post})

You can also pass in extras with a hash containing URL parameters that would normally be in the query string. This can be used to assert that values in the query string will end up in the params hash correctly. To test query strings you must use the extras argument because appending the query string on the path directly will not work. For example:

# Asserts that a path of '/items/list/1?view=print' returns the correct options
assert_recognizes({controller: 'items', action: 'list', id: '1', view: 'print'}, 'items/list/1', { view: "print" })

The message parameter allows you to pass in an error message that is displayed upon failure.

# Check the default route (i.e., the index action)
assert_recognizes({controller: 'items', action: 'index'}, 'items')

# Test a specific action
assert_recognizes({controller: 'items', action: 'list'}, 'items/list')

# Test an action with a parameter
assert_recognizes({controller: 'items', action: 'destroy', id: '1'}, 'items/destroy/1')

# Test a custom route
assert_recognizes({controller: 'items', action: 'show', id: '1'}, 'view/item1')

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 128
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

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

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

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

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

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

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

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

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 183
def method_missing(selector, *args, &block)
  if defined?(@controller) && @controller && defined?(@routes) && @routes && @routes.named_routes.route_defined?(selector)
    @controller.public_send(selector, *args, &block)
  else
    super
  end
end

ROUTES TODO: These assertions should really work in an integration context

# File actionpack/lib/action_dispatch/testing/assertions/routing.rb, line 153
def with_routing
  old_routes, @routes = @routes, ActionDispatch::Routing::RouteSet.new
  if defined?(@controller) && @controller
    old_controller, @controller = @controller, @controller.clone
    _routes = @routes

    @controller.singleton_class.include(_routes.url_helpers)

    if @controller.respond_to? :view_context_class
      view_context_class = Class.new(@controller.view_context_class) do
        include _routes.url_helpers
      end

      custom_view_context = Module.new {
        define_method(:view_context_class) do
          view_context_class
        end
      }
      @controller.extend(custom_view_context)
    end
  end
  yield @routes
ensure
  @routes = old_routes
  if defined?(@controller) && @controller
    @controller = old_controller
  end
end

A helper to make it easier to test different route configurations. This method temporarily replaces @routes with a new RouteSet instance.

The new instance is yielded to the passed block. Typically the block will create some routes using set.draw { match ... }:

with_routing do |set|
  set.draw do
    resources :users
  end
  assert_equal "/users", users_path
end