Fake helpers for http://thepugautomatic.com/2014/03/draper/#comment-2059556508

example_spec.rb

describe MyPresenter, "#my_method" do
  let(:view) { helper_instance }

  it "works" do
    actual = MyPresenter.new("whatever").my_method(view)
    expect(actual).to include "whatever"
  end
end

fake_helpers.rb

module MiscHelpers
  def helper_instance(helper_module = nil)
    Class.new {
      include helper_module if helper_module
      include FakeHelpers
    }.new
  end

  module FakeHelpers
    def capture
      @concatenated = []
      yielded = yield
      @concatenated << yielded if yielded.is_a?(String)
      @concatenated.join
    end

    def concat(something)
      @concatenated << something
    end

    def tag(name)
      "<#{name}>"
    end

    def content_tag(name, value_or_attributes, opts={}, &block)
      if block_given?
        attributes = value_or_attributes.map { |n, v| %{#{n}="#{v}"} }.join(" ")
        attributes = attributes.present? ? " #{attributes}" : ""
        value = yield
      else
        attributes = nil
        value = value_or_attributes
      end

      "<#{name}#{attributes}>#{value}</#{name}>"
    end

    def link_to(name, url, html_opts = nil)
      "<a href='#{url}'>#{name}</a>"
    end

    def mail_to(email)
      "<a href='mailto:#{email}'>#{email}</a>"
    end

    def asset_path(file)
      "/assets/#{file}"
    end

    def simple_format(text)
      "<p>%s</p>" % text.gsub("\n", "<br>")
    end

    def truncate(text, opts = {})
      text
    end
  end
end