1 files changed, 55 insertions, 0 deletions
diff --git a/qa/qa/page/view.rb b/qa/qa/page/view.rb
new file mode 100644
index 00000000000..6635e1ce039
--- /dev/null
+++ b/qa/qa/page/view.rb
@@ -0,0 +1,55 @@
+module QA
+  module Page
+    class View
+      attr_reader :path, :elements
+
+      def initialize(path, elements)
+        @path = path
+        @elements = elements
+      end
+
+      def pathname
+        @pathname ||= Pathname.new(File.join(__dir__, '../../../', @path))
+          .cleanpath.expand_path
+      end
+
+      def errors
+        unless pathname.readable?
+          return ["Missing view partial `#{pathname}`!"]
+        end
+
+        ##
+        # Reduce required elements by streaming view and making assertions on
+        # elements' existence.
+        #
+        @missing ||= @elements.dup.tap do |elements|
+          File.foreach(pathname.to_s) do |line|
+            elements.reject! { |element| element.matches?(line) }
+          end
+        end
+
+        @missing.map do |missing|
+          "Missing element `#{missing.name}` in `#{pathname}` view partial!"
+        end
+      end
+
+      def self.evaluate(&block)
+        Page::View::DSL.new.tap do |evaluator|
+          evaluator.instance_exec(&block) if block_given?
+        end
+      end
+
+      class DSL
+        attr_reader :elements
+
+        def initialize
+          @elements = []
+        end
+
+        def element(name, pattern = nil)
+          @elements.push(Page::Element.new(name, pattern))
+        end
+      end
+    end
+  end
+end