Michael Hartl's Rails 5 tutorial chapter 10 listing 10.56 Testing that the admin attribute is forbidden

I was trying to pass the exercise in listing 10.56 and test if the admin attribute is forbidden. I added admin parameter in

app/controllers/users_controller.rb

def user_params
      params.require(:user).permit(:name, :email, :password,
                                   :password_confirmation,
                                   :admin)
end

also, filled necessary parts in

test/controllers/users_controller_test.rb

test "should not allow the admin attribute to be edited via the web" do
      log_in_as(@other_user)
      assert_not @other_user.admin?
      patch :update, id: @other_user, user: { password: "",
                                              password_confirmation: "",
                                              admin: true }
      assert_not @other_user.reload.admin?
 end

Still, I am getting unknown error after test:

ERROR["test_should_not_allow_the_admin_attribute_to_be_edited_via_the_web", UsersControllerTest, 3.2600422599352896]
 test_should_not_allow_the_admin_attribute_to_be_edited_via_the_web#UsersControllerTest (3.26s)
URI::InvalidURIError:         URI::InvalidURIError: bad URI(is not URI?): http://www.example.com:80update
            test/controllers/users_controller_test.rb:37:in `block in <class:UsersControllerTest>'

Anyone here was dealing with the same problem?

Many thanks for any help)