Testing a Rails FormBuilder extension - ruby-on-rails

Question

I have created a FormBuilder extension:
form.div_field_with_label(:email)
Which outputs:
<div class="field email">
<label for="user_email">Email</label>
<input class="input" id="user_email" name="user[email]" type="email" value="">
</div>
How do i create or mock the template object in my rspec test?
app/helper/form_helper.rb
module FormHelper
class GroundedFormBuilder < ActionView::Helpers::FormBuilder
def div_field_with_label(key, &block)
if block_given?
content = self.label(key)
content << block.call(key)
end
classes = ['field']
classes << key.to_s
if #object.errors[key].size != 0
classes << 'warning'
msg = #object.errors.full_message(key, #object.errors[key].join(', '))
content << #template.content_tag(:p, msg, :class => "error-message warning alert" )
end
#template.content_tag(:div, content, :class => classes.join(' ').html_safe)
end
end
end
spec/helper/form_helper_spec.rb
require 'spec_helper'
describe FormHelper do
describe FormHelper::GroundedFormBuilder do
describe 'div_field_with_label' do
# how do i create or mock template?
# template = ?
let(:resource) { FactoryGirl.create :user }
let(:helper) { FormHelper::GroundedFormBuilder.new(:user, resource, template, {})}
let(:output) { helper.div_field_with_label :email }
it 'wraps input and label' do
expect(output).to match /<div class="field">/
end
it 'creates a label' do
expect(output).to match /<label for="user[email]">Email/
end
end
end
end

Answer 1

Update for rails 3 or higher.
This how it should looks like now:
require 'spec_helper'
class TestHelper < ActionView::Base; end
describe LabeledFormBuilder do
describe '#upload_tag' do
let(:helper) { TestHelper.new }
let(:resource) { FactoryGirl.build :user }
let(:builder) { LabeledFormBuilder.new :user, resource, helper, {}, nil }
let(:output) do
builder.upload_tag :avatar, title: "Test upload"
end
before { expect(helper).to receive(:render) { "render partial "} }
it { expect(output).to include "Upload file via new solution" }
end
end

Answer 2

I haven't tried this, but looking at how your GroundedFormBuilder uses #template, maybe all you need is an object that extends ActionView::Helpers::TagHelper:
# ...
template = Object.new.extend ActionView::Helpers::TagHelper
# ...
Any of the TagHelper methods such as content_tag should generate the same content as they would when included in a real template.

Answer 3

actually it was as easy as using self since FormBuilder has TagHelper somewhere in the inheritance chain.
# spec/helper/form_helper_spec.rb
require 'spec_helper'
describe FormHelper do
describe FormHelper::GroundedFormBuilder do
describe 'div_field_with_label' do
# how do i create or mock template?
# template = ?
let(:resource) { FactoryGirl.create :user }
let(:helper) { FormHelper::GroundedFormBuilder.new(:user, resource, self, {})}
let(:output) {
helper.div_field_with_label :email do
helper.email_field(:email, :class => 'input')
end
}
it 'wraps input and label' do
expect(output).to include '<div class="field email">'
end
it 'creates a label' do
expect(output).to include '<label'
end
end
end
end