Rspec, Rails - how to test helper method that use params hash?

Question

I want to implement a tagging system similar to stackoverflow, there is a box with a tags at top right corner, and also I have links to delete tag from params hash. my method works correctly in browser. But I can't find a way to test it.

def tags_list_with_destroy_links
    if params[:tags]
      li = ""
      p = params[:tags].split("+") # '/tagged/sea+ship+sun' => ['sea', 'ship', 'sun']
      p.map do |t|
        remove_link = if p.count  >= 3
                        c = p.reject {|item| item == t }
                        a = c.join("+")
                        {:tags => a}
                      elsif p.count == 2
                        c = p.reject {|item| item == t }
                        {tags: c[0]}
                      else
                        questions_url
                      end

        li << content_tag(:li) do
          link_to(t, questions_tags_path(t), class: 'tag') +
              link_to( '', remove_link , class: 'icon-small icons-cross')
        end
      end

      ul = content_tag(:ul, li.html_safe)
      ul << tag(:hr)
    end
  end

I've tried:

it 'return list with selected tags' do
      #Rails.application.routes.url_helpers.stub(:questions_tags).and_return('/questions/tagged/sea+ship+sun')
      #helper.request.stub(:path).and_return('/questions/tagged/sea+ship+sun')
      helper.stub(:url_for, {controller:'questions', action: 'index', tags:'sea+ship+sun'}  ).and_return('/questions/tagged/sea+ship+sun')
      helper.params[:tags] = 'sea+ship+sun'
      helper.tags_list_with_destroy_links.should == 'list_with_tags'
    end

but it return:

<a class=\"tag\" href=\"/questions/tagged/sea+ship+sun\">sea</a><a class=\"icon-small icons-cross\" href=\"/questions/tagged/sea+ship+sun\"></a></li>

and shoud return remove link as

href="/questions/tagged/ship+sun" without sea

I would appreciate any advice

Answer 1

The params field is going to come back parsed into the correct ruby data structures (hash, array, string, etc). There's no need to manually split items such as +, if there is a nested param it will return as part of the params object:

{tags: ["sea", "ship", "sun"]}

To access your data, or create an assumption about your param data existing in the test, you're going to want to create a stub. You're almost there, try something more along the lines of:

helper.stub!(:params).and_return({tags: ["sea", "ship", "sun"]})

Once you have the params stubbed correctly you can check the output of your helper method to ensure it's validity (this is called the expectation):

expect(helper.tags_list_with_destroy_links).to eq("some_url")