Add domain specific language to define QA page elements

qa/qa/page/base.rb

@@ -5,6 +5,9 @@ module QA
     class Base
       include Capybara::DSL
       include Scenario::Actable
+      extend SingleForwardable
+
+      def_delegators :evaluator, :view, :views
 
       def refresh
         visit current_url
@@ -40,6 +43,24 @@ module QA
       def self.path
         raise NotImplementedError
       end
+
+      def self.evaluator
+        @evaluator ||= Page::Base::DSL.new
+      end
+
+      class DSL
+        attr_reader :views
+
+        def initialize
+          @views = []
+        end
+
+        def view(path, &block)
+          Page::Element.evaluate(&block).tap do |elements|
+            @views.push(Page::View.new(path, elements))
+          end
+        end
+      end
     end
   end
 end

qa/qa/page/element.rb

@@ -1,6 +1,32 @@
 module QA
   module Page
     class Element
+      attr_reader :name
+
+      def initialize(name, pattern)
+        @name = name
+        @pattern = pattern
+      end
+
+      def self.evaluate(&block)
+        Page::Element::DSL.new.tap do |evaluator|
+          evaluator.instance_exec(&block)
+
+          return evaluator.elements
+        end
+      end
+
+      class DSL
+        attr_reader :elements
+
+        def initialize
+          @elements = []
+        end
+
+        def element(name, pattern)
+          @elements.push(Page::Element.new(name, pattern))
+        end
+      end
     end
   end
 end

qa/qa/page/view.rb

@@ -1,6 +1,12 @@
 module QA
   module Page
     class View
+      attr_reader :path, :elements
+
+      def initialize(path, elements)
+        @path = path
+        @elements = elements
+      end
     end
   end
 end

qa/spec/page/base_spec.rb

@@ -0,0 +1,35 @@
+describe QA::Page::Base do
+  describe 'page helpers' do
+    it 'exposes helpful page helpers' do
+      expect(subject).to respond_to :refresh, :wait, :scroll_to
+    end
+  end
+
+  describe 'DSL for defining view partials', '.view' do
+    subject do
+      Class.new(described_class) do
+        view 'path/to/some/view.html.haml' do
+          element :something, 'string pattern'
+          element :something_else, /regexp pattern/
+        end
+
+        view 'path/to/some/_partial.html.haml' do
+          element :something, 'string pattern'
+        end
+      end
+    end
+
+    it 'makes it possible to define page views' do
+      expect(subject.views.size).to eq 2
+      expect(subject.views).to all(be_an_instance_of QA::Page::View)
+    end
+
+    it 'populates views objects with data about elements' do
+      subject.views.first.elements.tap do |elements|
+        expect(elements.size).to eq 2
+        expect(elements).to all(be_an_instance_of QA::Page::Element)
+        expect(elements.map(&:name)).to eq [:something, :something_else]
+      end
+    end
+  end
+end