Ruby on Rails

test "should render js to show the change password form" do     sign_in_user       xhr :get, :enable_password_change       assert_template :enable_password_change     assert_response :ok     assert assigns(:merchant_user)  end

I have this controller:

class UsersController < ApplicationController    def enable_password_change      respond_to do |format|        format.js {          render :layout => false        }      end    end  end

And the following test:

test "should render js to show the change password form" do    sign_in_user    request_javascript    get :enable_password_change    assert_template :enable_password_change    assert_response :ok  end

And the helper method to set the request headers:

def request_javascript    @request.headers["Accepts"] = "text/javascript, application/javascript, application/ecmascript, application/x-ecmascript"  end

However my test reports:

Finished tests in 0.942294s, 7.4287 tests/s, 15.9186 assertions/s.    1) Error:  UsersControllerTest#test_should_render_js_to_show_the_change_password_for:  ActionController::UnknownFormat: ActionController::UnknownFormat  app/controllers/users_controller.rb:9:in `enable_password_change'  test/controllers/users_controller_test.rb:14:in `block in <class:UsersControllerTest>'    7 tests, 15 assertions, 0 failures, 1 errors, 0 skips

What am I doing wrong here?

P.S. Also posted on http://stackoverflow.com/questions/17870266/testing-if-a-controller-renders-a-js-template