Application Helper Spec，测试控制器特定的输出？

Question

I'm a little unsure as to how to write a test for a helper method which has output that is based on the given controller and action that are requested.

Given the following helper method in my application helper...

module ApplicationHelper
  def body_id
    [ controller.controller_name, controller.action_name ].join("_")
  end
end

... how would you write an application_helper_spec that tests this method?

Answer 1

Assign or mock the controller object. That will give you something to test against. (RSpec includes a very good mocking/stubbing library.)

Answer 2

rspec-rails has some built sugar for testing helpers as @marnen-laibow-koser mentioned. But I sometimes like to write very lightweight tests for my helpers that don't have to load in my whole rails environment. This way the tests can run in less than a second as opposed to the multiple seconds it takes to load the rails environment.

Here is an example:

require 'spec_helper_lite'
require_relative '../../app/helpers/application_helper'

describe ApplicationHelper do
  let(:helper) do
    class Helper
      include ApplicationHelper
    end
    Helper.new
  end

  it "formats an elapsed time as a number of minutes and seconds" do
    helper.elapsed_as_min_sec(90).should == "1min 30sec"
  end
end

And my spec_helper_lite.rb file just looks like this:

require 'rspec'
require 'rspec/autorun'

RSpec.configure do |config|
  config.order = "random"
end