```ruby
require "abstract_unit"
require "template/erb/helper"

module ERBTest
  class TagHelperTest < BlockTestCase

    extend ActiveSupport::Testing::Declarative

    test "percent equals works for content_tag and does not require parenthesis on method call" do
      assert_equal "<div>Hello world</div>", render_content("content_tag :div", "Hello world")
    end

    test "percent equals works for javascript_tag" do
      expected_output = "<script>\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
      assert_equal expected_output, render_content("javascript_tag", "alert('Hello')")
    end

    test "percent equals works for javascript_tag with options" do
      expected_output = "<script id=\"the_js_tag\">\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
      assert_equal expected_output, render_content("javascript_tag(:id => 'the_js_tag')", "alert('Hello')")
    end

    test "percent equals works with form tags" do
      expected_output = %r{<form.*action="foo".*method="post">.*hello*</form>}
      assert_match expected_output, render_content("form_tag('foo')", "<%= 'hello' %>")
    end

    test "percent equals works with fieldset tags" do
      expected_output = "<fieldset><legend>foo</legend>hello</fieldset>"
      assert_equal expected_output, render_content("field_set_tag('foo')", "<%= 'hello' %>")
    end
  end
end
```

Remove AS declarative extension from erb tag test
user
```ruby
require "abstract_unit"
require "template/erb/helper"

module ERBTest
  class TagHelperTest < BlockTestCase
    test "percent equals works for content_tag and does not require parenthesis on method call" do
      assert_equal "<div>Hello world</div>", render_content("content_tag :div", "Hello world")
    end

    test "percent equals works for javascript_tag" do
      expected_output = "<script>\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
      assert_equal expected_output, render_content("javascript_tag", "alert('Hello')")
    end

    test "percent equals works for javascript_tag with options" do
      expected_output = "<script id=\"the_js_tag\">\n//<![CDATA[\nalert('Hello')\n//]]>\n</script>"
      assert_equal expected_output, render_content("javascript_tag(:id => 'the_js_tag')", "alert('Hello')")
    end

    test "percent equals works with form tags" do
      expected_output = %r{<form.*action="foo".*method="post">.*hello*</form>}
      assert_match expected_output, render_content("form_tag('foo')", "<%= 'hello' %>")
    end

    test "percent equals works with fieldset tags" do
      expected_output = "<fieldset><legend>foo</legend>hello</fieldset>"
      assert_equal expected_output, render_content("field_set_tag('foo')", "<%= 'hello' %>")
    end
  end
end
```
assistant