Preference for helper specs?

gistfile1.rb

# Option 1:
#   Use content to separate the helper from the spec

it "should have something" do
  content = helper.some_helper_method
  content.should have_tag('a', :text => 'foo')
end

# Option 2:
#   Combine helper call and spec

it "should have something" do
  helper.some_helper_method.should have_tag('a', :text => 'bar')
end

# Option 3:
#  Use subject

context '#some_helper_method' do
  before :each do
    @params = 'foo'
  end

  subject { helper.some_helper_method(@params) }

  it { should have_tag 'a', :text => 'bar' }
end