Add lint tests

Gemfile

@@ -1,3 +1,4 @@
 source "https://rubygems.org"
 
 gem "github-pages"
+gem "rake"

Gemfile.lock

@@ -104,6 +104,7 @@ GEM
       sawyer (~> 0.7.0, >= 0.5.3)
     pkg-config (1.1.7)
     public_suffix (1.5.3)
+    rake (11.2.2)
     rb-fsevent (0.9.7)
     rb-inotify (0.9.7)
       ffi (>= 0.5.0)
@@ -125,6 +126,7 @@ PLATFORMS
 
 DEPENDENCIES
   github-pages
+  rake
 
 BUNDLED WITH
    1.12.5

Rakefile

@@ -0,0 +1,9 @@
+require "rake/testtask"
+Rake::TestTask.new do |t|
+  t.libs << "test"
+  t.test_files = FileList["test/*_test.rb"]
+  t.warning = false
+  t.verbose = false
+end
+
+task :default => :test

_config.yml

@@ -2,9 +2,11 @@ baseurl: "/open-source-handbook"
 
 exclude:
   - docs
+  - Gemfile*
+  - Rakefile
   - README.md
   - script
-  - Gemfile*
+  - test
 
 collections:
   content:

_data/fields.yml

@@ -0,0 +1,10 @@
+# Each piece of content has YAML front matter with these properties:
+
+title:
+  required: true
+
+next:
+  type: String
+
+previous:
+  type: String

test/helper.rb

@@ -0,0 +1,29 @@
+require "minitest/autorun"
+require "jekyll"
+
+module Helper
+  class << self
+    attr_accessor :config, :site
+  end
+end
+
+def source
+  File.expand_path('../', File.dirname(__FILE__))
+end
+
+def config
+  Helper.config ||= Jekyll.configuration("source" => source)
+end
+
+def content
+  site.collections['content'].docs.map { |doc| doc.to_liquid }
+end
+
+def site
+  Helper.site ||= begin
+    site = Jekyll::Site.new(config)
+    site.reset
+    site.read
+    site
+  end
+end

test/lint_test.rb

@@ -0,0 +1,36 @@
+require_relative "./helper"
+
+describe "lint test" do
+
+  content.each do |page|
+
+    describe page["path"] do
+
+      describe "frontmatter" do
+
+        before do
+          # Load raw metadata to skip defaults
+          @data = SafeYAML.load_file(page["path"])
+        end
+
+        it "contains supported fields" do
+          extra_fields = @data.keys - site.data["fields"].keys
+          assert extra_fields.empty?, "Unexpected metadata in #{page["path"]}: #{extra_fields.inspect}"
+        end
+
+        site.data["fields"].each do |name, attrs|
+          it "#{name} is required" do
+            assert @data.key?(name), "#{name} is required"
+          end if attrs["required"]
+
+          it "#{name} should be of type #{attrs["type"]}" do
+            assert_kind_of Kernel.const_get(attrs["type"]), @data[name] if @data[name]
+          end if attrs["type"]
+
+          it "#{name} has valid attributes" do
+          end
+        end
+      end
+    end
+  end
+end