```ruby
require 'test_helper'

#
# == LanguageHelper Test
#
class LanguageHelperTest < ActionView::TestCase
  include LanguageHelper

  test 'should return true if current locale is right' do
    params[:locale] = :fr
    assert current_locale?(:fr)
  end

  test 'should return false if current locale is wrong' do
    params[:locale] = :fr
    assert_not current_locale?(:en)
  end
end
```

Add more tests for language helper
user
```ruby
require 'test_helper'

#
# == LanguageHelper Test
#
class LanguageHelperTest < ActionView::TestCase
  include LanguageHelper
  include FontAwesome::Rails::IconHelper

  setup :initialize_test

  test 'should return true if current locale is right' do
    params[:locale] = :fr
    assert current_locale?(:fr)
  end

  test 'should return false if current locale is wrong' do
    params[:locale] = :fr
    assert_not current_locale?(:en)
  end

  test 'should return correct class if tested locale is true' do
    params[:locale] = :fr
    assert_equal 'l-nav-item-active', active_language(:fr)
    assert_nil active_language(:en)
  end

  test 'should correctly format in html link language' do
    params[:locale] = :fr
    assert_equal '<a class="l-nav-item-link" href="#">Français <i class="fa fa-check"></i></a>', current_link_language('check', I18n.t("active_admin.globalize.language.#{params[:locale]}"))
  end

  test 'should return correct slug article by locale' do
    params[:locale] = :fr
    assert_equal 'developpement-hebergement', slug_for_locale(posts(:about), :fr)
    assert_equal 'site-hosting', slug_for_locale(posts(:about), :en)
  end

  private

  def initialize_test
    @locales = I18n.available_locales
  end
end
```
assistant