Add govspeak translator component

- add basic component, documentation and tests
- we do not demonstrate all possible govspeak options as this is handled by the main component already
- update all components spec to ignore new component, as no stylesheet

Author: andysellick

app/helpers/govspeak_translator_helper.rb

@@ -0,0 +1,8 @@
+require "govspeak"
+
+module GovspeakTranslatorHelper
+  def parse_govspeak(block)
+    doc = Govspeak::Document.new(block.strip)
+    doc.to_html.strip
+  end
+end

app/views/components/_govspeak_translator.html.erb

@@ -0,0 +1,8 @@
+<% content = capture do %>
+  <%= yield %>
+<% end %>
+<% if content.strip.length > 0 %>
+  <%= render "govuk_publishing_components/components/govspeak", {} do %>
+    <%= raw parse_govspeak(content) %>
+  <% end %>
+<% end %>

app/views/components/docs/govspeak_translator.yml

@@ -0,0 +1,30 @@
+name: Govspeak translator
+description: Translates govspeak markdown into HTML.
+body: |
+  This component wraps the existing [govspeak component](https://components.publishing.service.gov.uk/component-guide/govspeak) from govuk_publishing_components but instead of displaying previously generated HTML it accepts govspeak markdown and converts it into markup.
+
+  There is a quirk of displaying this in the component guide where if the first line of the markdown is a heading, it is converted into a paragraph. Current testing shows that the conversion works correctly in practice.
+accessibility_criteria: |
+  - headings must be part of a correct heading structure for the page
+  - text should have a text contrast ratio higher than 4.5:1 against the background colour to meet WCAG AA
+shared_accessibility_criteria:
+  - link
+examples:
+  default:
+    data:
+      block: |
+        This is a paragraph. See how it looks.
+
+        * This is a list item
+        * This is another list item
+        * One more list item
+
+        ###A heading
+
+        And now an address.
+
+        $A
+        HM Revenue and Customs
+        Bradford
+        BD98 1YY
+        $A

spec/components/all_components_spec.rb

@@ -18,7 +18,7 @@
         expect(yaml["accessibility_criteria"] || yaml["shared_accessibility_criteria"]).to be_truthy
       end
 
-      it "has the correct class in the ERB template" do
+      it "has the correct class in the ERB template", skip: component_name.in?(%w[govspeak_translator]) do
         erb = File.read(filename)
         class_name = "app-c-#{component_name.dasherize}"
         expect(erb).to include(class_name)
@@ -34,7 +34,7 @@
         expect(File).to exist(rspec_file)
       end
 
-      it "has a correctly named SCSS file" do
+      it "has a correctly named SCSS file", skip: component_name.in?(%w[govspeak_translator]) do
         css_file = "#{__dir__}/../../app/assets/stylesheets/components/_#{component_name.tr('_', '-')}.scss"
         expect(File).to exist(css_file)
       end

spec/components/govspeak_translator_spec.rb

@@ -0,0 +1,17 @@
+RSpec.describe "GovspeakTranslatorComponent", type: :view do
+  def component_name
+    "govspeak_translator"
+  end
+
+  it "renders nothing when required params are not passed" do
+    expect(render_component({})).to be_empty
+  end
+
+  it "transforms simple markdown into markup" do
+    render "components/#{component_name}" do
+      "##heading"
+    end
+
+    expect(rendered).to include("<h2 id=\"heading\">heading</h2>")
+  end
+end

spec/helpers/govspeak_translator_helper_spec.rb

@@ -0,0 +1,22 @@
+RSpec.describe GovspeakTranslatorHelper do
+  describe "#parse_govspeak" do
+    it "converts simple govspeak into markup" do
+      str = "#heading"
+      expect(parse_govspeak(str)).to eq("<h1 id=\"heading\">heading</h1>")
+    end
+
+    it "converts multi line govspeak into markup" do
+      str = "
+#heading
+
+This is a paragraph
+      "
+      expect(parse_govspeak(str)).to eq("<h1 id=\"heading\">heading</h1>\n\n<p>This is a paragraph</p>")
+    end
+
+    it "ignores formatting" do
+      str = "\n\t\t\t#heading\n\n\t"
+      expect(parse_govspeak(str)).to eq("<h1 id=\"heading\">heading</h1>")
+    end
+  end
+end