Add Rails integration test for compiled template

We want to be confident that the changes we make to govuk_template don't
break the compiled templates. The only way we can really do this automatically
is to have code that can process each template.

The spec is currently wired up to anything and is hardcoded for the filename
generated by the Rails integration code. The expectations should be portable,
however.

This needs some scripting to trigger the sub-build within each integration
testing app and then run the spec. For the languages that aren't Ruby, we'll
need to alter the travis.yml.

.gitignore

@@ -1,6 +1,8 @@
 .DS_Store
 .bundle
 .sass-cache
-Gemfile.lock
-app
+/Gemfile.lock
+/app
 pkg
+
+integration_tests/html_for_testing/*.html

govuk_template.gemspec

@@ -24,6 +24,8 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'govuk_frontend_toolkit', '3.5.1'
   spec.add_development_dependency 'gem_publisher', '1.3.0'
   spec.add_development_dependency 'rspec', '3.2.0'
+  spec.add_development_dependency 'rspec-html-matchers', '0.7.0'
   spec.add_development_dependency 'mustache', '0.99.7'
+  spec.add_development_dependency 'nokogiri', '1.6.6.2'
   spec.add_development_dependency 'octokit', '3.4.2'
 end

integration_tests/README.md

@@ -0,0 +1,10 @@
+# Integration Tests
+
+When we make changes to govuk_template, we want to know that the changes don't break integration with clients.
+
+This directory contains example integrations for compilation targets of govuk_template so that we can test two things:
+
+* is the compiled template still syntactically valid?
+* has the API changed - has it required any changes in the app?
+
+This is achieved by getting each app to render HTML from the template, saving it into `./html_for_testing` and then running assertions against each of those HTML files.

integration_tests/html_rendered_by_each_integration_testing_app_spec.rb

@@ -0,0 +1,82 @@
+require 'spec_helper'
+require 'rspec-html-matchers'
+
+describe "HTML rendered by each integration testing app" do
+  include RSpecHtmlMatchers
+
+  let(:filename) { "#{PROJECT_ROOT}/integration_tests/html_for_testing/rails_integration_test_app.html" }
+
+  subject { File.open(filename).read }
+
+  it "should allow overriding the lang attribute on the html tag" do
+    expect(subject).to have_tag("html", with: { lang: 'rb' })
+  end
+
+  it "should allow overriding the page title" do
+    expect(subject).to have_tag("title", text: "This is a custom page title")
+  end
+
+  it "should allows inserting content into the head" do
+    expect(subject).to have_tag("head") do
+      with_tag "inserted-into-head"
+    end
+  end
+
+  it "should allow setting_body_classes" do
+    expect(subject).to have_tag("body", with: { class: "custom_body_class" })
+  end
+
+  it "should allow inserting content into body_start" do
+    expect(subject).to have_tag("body") do
+      with_tag "inserted-into-body-start"
+    end
+  end
+
+  it "should allow overriding the cookie message" do
+    expect(subject).to have_tag("div#global-cookie-message", text: /Custom cookie message/)
+  end
+
+  it "should allow setting_global_header_class" do
+    expect(subject).to have_tag("header", with: { class: "custom_header_class" })
+  end
+
+  it "should allow inserting content into the header" do
+    expect(subject).to have_tag("header") do
+      with_tag("inside-header")
+    end
+  end
+
+  it "should allow inserting_a_proposition_header" do
+    expect(subject).to have_tag("header") do
+      with_tag("proposition-header")
+    end
+  end
+
+  it "should allow inserting_after_header" do
+    expect(subject).to have_tag("body") do
+      with_tag("after-header")
+    end
+  end
+
+  it "should content" do
+    expect(subject).to have_tag("body", text: /The page content/)
+  end
+
+  it "should footer_top" do
+    expect(subject).to have_tag("footer") do
+      with_tag "footer-top"
+    end
+  end
+
+  it "should footer_support_links" do
+    expect(subject).to have_tag("footer") do
+      with_tag "footer-support-links"
+    end
+  end
+
+  it "should body_end" do
+    expect(subject).to have_tag("body") do
+      with_tag "body-end"
+    end
+  end
+end

integration_tests/integrations/rails/Gemfile

@@ -0,0 +1,3 @@
+source "https://rubygems.org"
+
+gem "actionpack", "4.2.1"

integration_tests/integrations/rails/Gemfile.lock

@@ -0,0 +1,52 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    actionpack (4.2.1)
+      actionview (= 4.2.1)
+      activesupport (= 4.2.1)
+      rack (~> 1.6)
+      rack-test (~> 0.6.2)
+      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-html-sanitizer (~> 1.0, >= 1.0.1)
+    actionview (4.2.1)
+      activesupport (= 4.2.1)
+      builder (~> 3.1)
+      erubis (~> 2.7.0)
+      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-html-sanitizer (~> 1.0, >= 1.0.1)
+    activesupport (4.2.1)
+      i18n (~> 0.7)
+      json (~> 1.7, >= 1.7.7)
+      minitest (~> 5.1)
+      thread_safe (~> 0.3, >= 0.3.4)
+      tzinfo (~> 1.1)
+    builder (3.2.2)
+    erubis (2.7.0)
+    i18n (0.7.0)
+    json (1.8.2)
+    loofah (2.0.2)
+      nokogiri (>= 1.5.9)
+    mini_portile (0.6.2)
+    minitest (5.6.1)
+    nokogiri (1.6.6.2)
+      mini_portile (~> 0.6.0)
+    rack (1.6.1)
+    rack-test (0.6.3)
+      rack (>= 1.0)
+    rails-deprecated_sanitizer (1.0.3)
+      activesupport (>= 4.2.0.alpha)
+    rails-dom-testing (1.0.6)
+      activesupport (>= 4.2.0.beta, < 5.0)
+      nokogiri (~> 1.6.0)
+      rails-deprecated_sanitizer (>= 1.0.1)
+    rails-html-sanitizer (1.0.2)
+      loofah (~> 2.0)
+    thread_safe (0.3.5)
+    tzinfo (1.2.2)
+      thread_safe (~> 0.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  actionpack (= 4.2.1)

integration_tests/integrations/rails/build.sh

@@ -0,0 +1,6 @@
+#! /bin/bash
+set -e
+
+bundle install
+
+bundle exec ruby simplicity.rb

integration_tests/integrations/rails/simplicity.rb

@@ -0,0 +1,26 @@
+require 'action_controller'
+
+class TemplateRenderer < AbstractController::Base
+  include AbstractController::Rendering
+  include ActionView::Layouts
+  include AbstractController::Helpers
+  include AbstractController::Translation
+  include AbstractController::AssetPaths
+
+  self.view_paths = [
+    "views",
+    File.absolute_path(File.expand_path(File.join(__FILE__, "../../../../app/views"))) # Hack to manually add the compiled template path
+  ]
+
+  layout "govuk_template"
+
+  def show
+    render template: "show"
+  end
+end
+
+rendered_template = TemplateRenderer.new.show
+
+output_filepath = File.absolute_path(File.expand_path(File.join(__FILE__, "../../../html_for_testing/rails_integration_test_app.html")))
+
+File.write(output_filepath, rendered_template)

integration_tests/integrations/rails/views/show.html.erb

@@ -0,0 +1,27 @@
+<% content_for(:html_lang, 'rb') %>
+
+<% content_for(:page_title, "This is a custom page title") %>
+
+<% content_for(:head) do %><inserted-into-head></inserted-into-head><% end %>
+
+<% content_for(:body_classes, "custom_body_class") %>
+
+<% content_for(:body_start) do %><inserted-into-body-start></inserted-into-body-start><% end %>
+
+<% content_for(:cookie_message, "Custom cookie message") %>
+
+<% content_for(:header_class, "custom_header_class") %>
+
+<% content_for(:inside_header) do %><inside-header></inside-header><% end %>
+
+<% content_for(:proposition_header) do %><proposition-header></proposition-header><% end %>
+
+<% content_for(:after_header) do %><after-header></after-header><% end %>
+
+The page content
+
+<% content_for(:footer_top) do %><footer-top></footer-top><% end %>
+
+<% content_for(:footer_support_links) do %><footer-support-links></footer-support-links><% end %>
+
+<% content_for(:body_end) do %><body-end></body-end><% end %>