refact: extracted default reporter

lib/capybara/screenshot/diff.rb

@@ -7,8 +7,11 @@
 require "capybara/screenshot/diff/test_methods"
 require "capybara/screenshot/diff/screenshoter"
 
+require "capybara/screenshot/diff/reporters/default"
+
 module Capybara
   module Screenshot
+
     mattr_accessor :add_driver_path
     mattr_accessor :add_os_path
     mattr_accessor :blur_active_element

lib/capybara/screenshot/diff/difference.rb

@@ -5,9 +5,13 @@
 module Capybara
   module Screenshot
     module Diff
-      class Difference < Struct.new(:region, :meta, :comparison)
+      class Difference < Struct.new(:region, :meta, :comparison, :failed_by)
         def different?
-          !(blank? || tolerable?)
+          failed? || !(blank? || tolerable?)
+        end
+
+        def failed?
+          !!failed_by
         end
 
         def base_image

lib/capybara/screenshot/diff/image_compare.rb

@@ -30,6 +30,7 @@ def initialize(image_path, base_image_path, options = {})
           @driver_options = options.dup
 
           @driver = Drivers.for(@driver_options)
+          @reporter = Capybara::Screenshot::Diff::Reporters::Default.new(self, @annotated_image_path, @annotated_base_image_path)
         end
 
         def self.build(image_path, base_image_path, options = {})
@@ -68,24 +69,23 @@ def quick_equal?
         def different?
           @error_message = nil
 
-          @error_message = _different?
+          @difference = find_difference
 
-          clean_tmp_files unless @error_message
+          @error_message = reporter.generate(@difference)
 
-          !@error_message.nil?
+          clean_tmp_files unless @difference.different?
+
+          @difference.different?
         end
 
         def build_error_for_different_dimensions(comparison)
-          change_msg = [comparison.base_image, comparison.new_image]
-            .map { |i| driver.dimension(i).join("x") }
-            .join(" => ")
-
-          "Screenshot dimension has been changed for #{@new_file_name}: #{change_msg}"
+          reporter.build_error_for_different_dimensions(
+            { comparison: comparison, new_file_name: new_file_name }
+          )
         end
 
         def clean_tmp_files
-          @annotated_base_image_path.unlink if @annotated_base_image_path.exist?
-          @annotated_image_path.unlink if @annotated_image_path.exist?
+          reporter.clean_tmp_files
         end
 
         def save(image, image_path)
@@ -106,22 +106,26 @@ def without_tolerable_options?
           (@driver_options.keys & TOLERABLE_OPTIONS).empty?
         end
 
-        def _different?
-          raise "There is no original (base) screenshot version to compare, located: #{@base_image_path}" unless @base_image_path.exist?
-          raise "There is no new screenshot version to compare, located: #{@image_path}" unless @image_path.exist?
+        def find_difference
+          raise ArgumentError, "There is no original (base) screenshot version to compare, located: #{@base_image_path}" unless @base_image_path.exist?
+          raise ArgumentError, "There is no new screenshot version to compare, located: #{@image_path}" unless @image_path.exist?
 
           comparison = load_and_process_images
 
           unless driver.same_dimension?(comparison)
-            return build_error_for_different_dimensions(comparison)
+            return Difference.new(
+              nil,
+              { difference_level: nil, max_color_distance: 0 },
+              self,
+              { different_dimensions: { comparison: comparison, new_file_name: new_file_name } }
+            )
           end
 
-          return not_different if driver.same_pixels?(comparison)
-
-          @difference = driver.find_difference_region(comparison)
-          return not_different unless @difference.different?
-
-          different(@difference)
+          if driver.same_pixels?(comparison)
+            no_difference
+          else
+            driver.find_difference_region(comparison)
+          end
         end
 
         def load_and_process_images
@@ -130,15 +134,6 @@ def load_and_process_images
           Comparison.new(new_image, base_image, @driver_options)
         end
 
-        def build_error_message(difference)
-          [
-            "(#{difference.inspect})",
-            new_file_name,
-            annotated_base_image_path.to_path,
-            annotated_image_path.to_path
-          ].join(NEW_LINE)
-        end
-
         def skip_area
           @driver_options[:skip_area]
         end
@@ -151,11 +146,6 @@ def dimensions
           @driver_options[:dimensions]
         end
 
-        def different(difference)
-          annotate_and_save_images(difference)
-          build_error_message(difference)
-        end
-
         def preprocess_images(images)
           images.map { |image| preprocess_image(image) }
         end
@@ -191,33 +181,17 @@ def new_file_size
         end
 
         def not_different
-          nil
-        end
-
-        def annotate_and_save_images(difference)
-          annotate_and_save_image(difference, difference.comparison.new_image, @annotated_image_path)
-          annotate_and_save_image(difference, difference.comparison.base_image, @annotated_base_image_path)
+          no_difference.different? || nil
         end
 
-        def annotate_and_save_image(difference, image, image_path)
-          image = annotate_difference(image, difference.region)
-          image = annotate_skip_areas(image, difference.skip_area) if difference.skip_area
-          save(image, image_path.to_path)
+        def no_difference
+          @difference = Difference.new(nil, { difference_level: nil, max_color_distance: 0 }, self).freeze
         end
 
-        DIFF_COLOR = [255, 0, 0, 255].freeze
-
-        def annotate_difference(image, region)
-          driver.draw_rectangles([image], region, DIFF_COLOR, offset: 1).first
+        def reporter
+          @reporter ||= Capybara::Screenshot::Diff::Reporters::Default.new(self)
         end
 
-        SKIP_COLOR = [255, 192, 0, 255].freeze
-
-        def annotate_skip_areas(image, skip_areas)
-          skip_areas.reduce(image) do |memo, region|
-            driver.draw_rectangles([memo], region, SKIP_COLOR).first
-          end
-        end
       end
 
       class Comparison < Struct.new(:new_image, :base_image, :options)

lib/capybara/screenshot/diff/reporters/default.rb

@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+module Capybara::Screenshot::Diff
+  module Reporters
+    class Default
+      attr_reader :comparer, :annotated_image_path, :annotated_base_image_path
+
+      def initialize(comparer, annotated_image_path = nil, annotated_base_image_path = nil)
+        @comparer = comparer
+        @annotated_image_path = annotated_image_path || comparer.annotated_image_path
+        @annotated_base_image_path = annotated_base_image_path || comparer.annotated_base_image_path
+      end
+
+      def generate(difference)
+        return nil unless difference.different?
+
+        if difference.failed? && difference.failed_by[:different_dimensions]
+          return build_error_for_different_dimensions(difference.failed_by[:different_dimensions])
+        end
+
+        annotate_and_save_images(difference)
+        build_error_message(difference)
+      end
+
+
+      def clean_tmp_files
+        annotated_base_image_path.unlink if annotated_base_image_path.exist?
+        annotated_image_path.unlink if annotated_image_path.exist?
+      end
+
+      def build_error_for_different_dimensions(failed_by)
+        comparison, new_file_name = failed_by[:comparison], failed_by[:new_file_name]
+        change_msg = [comparison.base_image, comparison.new_image]
+          .map { |i| driver.dimension(i).join("x") }
+          .join(" => ")
+
+        "Screenshot dimension has been changed for #{new_file_name}: #{change_msg}"
+      end
+
+      def annotate_and_save_images(difference)
+        annotate_and_save_image(difference, difference.comparison.new_image, annotated_image_path)
+        annotate_and_save_image(difference, difference.comparison.base_image, annotated_base_image_path)
+      end
+
+      def annotate_and_save_image(difference, image, image_path)
+        image = annotate_difference(image, difference.region)
+        image = annotate_skip_areas(image, difference.skip_area) if difference.skip_area
+
+        save(image, image_path.to_path)
+      end
+
+      DIFF_COLOR = [255, 0, 0, 255].freeze
+
+      def annotate_difference(image, region)
+        driver.draw_rectangles([image], region, DIFF_COLOR, offset: 1).first
+      end
+
+      SKIP_COLOR = [255, 192, 0, 255].freeze
+
+      def annotate_skip_areas(image, skip_areas)
+        skip_areas.reduce(image) do |memo, region|
+          driver.draw_rectangles([memo], region, SKIP_COLOR).first
+        end
+      end
+
+      def save(image, image_path)
+        driver.save_image_to(image, image_path.to_s)
+      end
+
+      NEW_LINE = "\n".freeze
+
+      def build_error_message(difference)
+        [
+          "(#{difference.inspect})",
+          new_file_name,
+          annotated_base_image_path.to_path,
+          annotated_image_path.to_path
+        ].join(NEW_LINE)
+      end
+
+      private
+
+      def reporter
+        self
+      end
+
+      def driver
+        @comparer.driver
+      end
+
+      def new_file_name
+        @comparer.new_file_name
+      end
+    end
+  end
+end

sig/capybara/screenshot/diff/image_compare.rbs

@@ -64,7 +64,7 @@ module Capybara
 
         private
 
-        def _different?: -> String?
+        def find_difference: -> Difference
 
         def different: (Difference images) -> String
 

test/capybara/screenshot/diff/difference_test.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "capybara/screenshot/diff/difference"
+
+module Capybara::Screenshot::Diff
+  class DifferenceTest < ActiveSupport::TestCase
+    class WithFailedByTest < DifferenceTest
+      setup do
+        @difference = Difference.new(nil, {}, nil, { different_dimensions: [] })
+      end
+
+      test 'it is different' do
+        assert_predicate @difference, :different?
+      end
+
+      test 'it is failed' do
+        assert_predicate @difference, :failed?
+      end
+    end
+  end
+end