rails testing helpers with instance variable?

I want to test a helper where I use a instance variable inside. I'm using rails 2.3 with the default testing framework. Can please someone write my a simple test (I guess a Unit test) for this? thanks

A simpler version of my code as example.

# controller
@bla = "some value"

# view
<%= foo %>

开发者_如何学编程# helper

def foo
  @bla.reverse
end

or is it a better practice to write this helper with a parameter call?

def foo(s)
  s.reverse
end

You can test helpers quite easily and it's built into the test framework, so i'm not sure what jasonpgignac is saying.

Under test/unit/helpers you will see all of your helpers generated by your script/generate scaffold or controller... however you generate them.

Inside said file, you can just assert that a value is equal, because you are just testing to make sure the result is coming up how you expect. Here's one i pulled from my code:

require 'test_helper'

class PaymentsHelperTest < ActionView::TestCase
  test "displays Month names" do
    assert_equal "April 2010", month_and_year_name(payment_transactions(:one))
  end
end

It's been awhile since i wrote this, but you call the actual helper in your assertion. In this case my helper was called month_and_year_name and i passed a fixture to it.

Easy stuff, that comes with the greatest testing framework known to man, test::unit and fixtures... as god intended.

Perhaps I'm missing something, but in the example you gave, you pretty much just wrote a one-to-one wrapper around the reverse function? What are you trying to do?

As for tests, there isn't a direct method to test helpers in the test suite that comes with rails, but there is a plugin that adds this functionality: http://nubyonrails.com/articles/test-your-helpers. I haven't used it in a while, but I think it still works.